Pub Date : 2005-06-01DOI: 10.5089/9781451861488.001
Richard Podpiera, M. Čihák
We analyze the structure, performance, and role of banking systems in the three member countries of the East African CommunityKenya, Tanzania, and Ugandaagainst the backdrop of recent financial sector reforms. Focusing on the behavior of different types of banks, we find no support for the argument that the presence of large international banks would have an adverse effect on the effectiveness and efficiency of banking sectors in developing countries. International banks are generally more efficient and more active in lending than domestic banks. However, as suggested by the Kenyan experience, the presence of international banks may not lead to increased competition and provision of banking services if weak institutions are allowed to remain in the system.
{"title":"Bank Behavior in Developing Countries: Evidence from East Africa","authors":"Richard Podpiera, M. Čihák","doi":"10.5089/9781451861488.001","DOIUrl":"https://doi.org/10.5089/9781451861488.001","url":null,"abstract":"We analyze the structure, performance, and role of banking systems in the three member countries of the East African Community\u0014Kenya, Tanzania, and Uganda\u0014against the backdrop of recent financial sector reforms. Focusing on the behavior of different types of banks, we find no support for the argument that the presence of large international banks would have an adverse effect on the effectiveness and efficiency of banking sectors in developing countries. International banks are generally more efficient and more active in lending than domestic banks. However, as suggested by the Kenyan experience, the presence of international banks may not lead to increased competition and provision of banking services if weak institutions are allowed to remain in the system.","PeriodicalId":163698,"journal":{"name":"Institutional & Transition Economics eJournal","volume":"1635 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115833864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-01DOI: 10.5089/9781451861419.001.A001
J. Irving
This paper assesses whether regional cooperation and integration of stock exchanges in eastern and southern Africa could offer a way of overcoming impediments to the exchanges` development. The paper concludes that regional cooperation and, at a later stage, integration, if carried out at the right pace and in a pragmatic way, could improve the liquidity, efficiency, and competitiveness of these exchanges. Further progress in developing national financial markets must precede any actual moves to integrate securities markets. These exchanges could meanwhile benefit from closer cooperation, including by encouraging more crossborder listings and information/technology sharing.
{"title":"Regional Integration of Stock Exchanges in Eastern and Southern Africa: Progress and Prospects","authors":"J. Irving","doi":"10.5089/9781451861419.001.A001","DOIUrl":"https://doi.org/10.5089/9781451861419.001.A001","url":null,"abstract":"This paper assesses whether regional cooperation and integration of stock exchanges in eastern and southern Africa could offer a way of overcoming impediments to the exchanges` development. The paper concludes that regional cooperation and, at a later stage, integration, if carried out at the right pace and in a pragmatic way, could improve the liquidity, efficiency, and competitiveness of these exchanges. Further progress in developing national financial markets must precede any actual moves to integrate securities markets. These exchanges could meanwhile benefit from closer cooperation, including by encouraging more crossborder listings and information/technology sharing.","PeriodicalId":163698,"journal":{"name":"Institutional & Transition Economics eJournal","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115895053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
PricedynamicsinIndiancitieswereexaminedusingcointegrationanalysis.Weidentifiedandcalculateda commontrendforprices in25majorcities inIndia.Impulseresponsefunctionswere obtainedtocalculatethe rates of convergence to the prices and we found that the half-life of any shock is very small for Indian cities. Althougha close to3-monthhalf-life seemstoofast,thereissomeindicationinthe literaturethat half-life can bemuchsmallerthantheconventionalratesof3‐5years.Wehavecalculatedhalf-lifeusingthepanelunitroot method,andfoundthatestimatesofhalf-lifefromcointegrationanalysisprovideafasterconvergenceratethan estimates using the panel unit root method. We also analyzed how shock can be transmitted from one city to another and found no systematic behavior of transmission from one city to another.
{"title":"Price Convergence Among Indian Cities: A Cointegration Approach","authors":"A. M. Morshed, Sung K. Ahn, Minsoo Lee","doi":"10.2139/ssrn.877335","DOIUrl":"https://doi.org/10.2139/ssrn.877335","url":null,"abstract":"PricedynamicsinIndiancitieswereexaminedusingcointegrationanalysis.Weidentifiedandcalculateda commontrendforprices in25majorcities inIndia.Impulseresponsefunctionswere obtainedtocalculatethe rates of convergence to the prices and we found that the half-life of any shock is very small for Indian cities. Althougha close to3-monthhalf-life seemstoofast,thereissomeindicationinthe literaturethat half-life can bemuchsmallerthantheconventionalratesof3‐5years.Wehavecalculatedhalf-lifeusingthepanelunitroot method,andfoundthatestimatesofhalf-lifefromcointegrationanalysisprovideafasterconvergenceratethan estimates using the panel unit root method. We also analyzed how shock can be transmitted from one city to another and found no systematic behavior of transmission from one city to another.","PeriodicalId":163698,"journal":{"name":"Institutional & Transition Economics eJournal","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122403822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniel A. Kaufmann, Aart C. Kraay, Massimo Mastruzzi
The authors present the latest update of their aggregate governance indicators, together with new analysis of several issues related to the use of these measures. The governance indicators measure the following six dimensions of governance: (1) voice and accountability; (2) political instability and violence; (3) government effectiveness; (4) regulatory quality; (5) rule of law, and (6) control of corruption. They cover 209 countries and territories for 1996, 1998, 2000, 2002, and 2004. They are based on several hundred individual variables measuring perceptions of governance, drawn from 37 separate data sources constructed by 31 organizations. The authors present estimates of the six dimensions of governance for each period, as well as margins of error capturing the range of likely values for each country. These margins of error are not unique to perceptions-based measures of governance, but are an important feature of all efforts to measure governance, including objective indicators. In fact, the authors give examples of how individual objective measures provide an incomplete picture of even the quite particular dimensions of governance that they are intended to measure. The authors also analyze in detail changes over time in their estimates of governance; provide a framework for assessing the statistical significance of changes in governance; and suggest a simple rule of thumb for identifying statistically significant changes in country governance over time. The ability to identify significant changes in governance over time is much higher for aggregate indicators than for any individual indicator. While the authors find that the quality of governance in a number of countries has changed significantly (in both directions), they also provide evidence suggesting that there are no trends, for better or worse, in global averages of governance. Finally, they interpret the strong observed correlation between income and governance, and argue against recent efforts to apply a discount to governance performance in low-income countries.
{"title":"Governance Matters IV: Governance Indicators for 1996-2004","authors":"Daniel A. Kaufmann, Aart C. Kraay, Massimo Mastruzzi","doi":"10.1596/1813-9450-3630","DOIUrl":"https://doi.org/10.1596/1813-9450-3630","url":null,"abstract":"The authors present the latest update of their aggregate governance indicators, together with new analysis of several issues related to the use of these measures. The governance indicators measure the following six dimensions of governance: (1) voice and accountability; (2) political instability and violence; (3) government effectiveness; (4) regulatory quality; (5) rule of law, and (6) control of corruption. They cover 209 countries and territories for 1996, 1998, 2000, 2002, and 2004. They are based on several hundred individual variables measuring perceptions of governance, drawn from 37 separate data sources constructed by 31 organizations. The authors present estimates of the six dimensions of governance for each period, as well as margins of error capturing the range of likely values for each country. These margins of error are not unique to perceptions-based measures of governance, but are an important feature of all efforts to measure governance, including objective indicators. In fact, the authors give examples of how individual objective measures provide an incomplete picture of even the quite particular dimensions of governance that they are intended to measure. The authors also analyze in detail changes over time in their estimates of governance; provide a framework for assessing the statistical significance of changes in governance; and suggest a simple rule of thumb for identifying statistically significant changes in country governance over time. The ability to identify significant changes in governance over time is much higher for aggregate indicators than for any individual indicator. While the authors find that the quality of governance in a number of countries has changed significantly (in both directions), they also provide evidence suggesting that there are no trends, for better or worse, in global averages of governance. Finally, they interpret the strong observed correlation between income and governance, and argue against recent efforts to apply a discount to governance performance in low-income countries.","PeriodicalId":163698,"journal":{"name":"Institutional & Transition Economics eJournal","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127054684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper identifies systematic performance differences between younger and older democracies: younger democracies are more corrupt; exhibit less rule of law, lower levels of bureaucratic quality, and lower secondary school enrollments; and spend more on public investment and government workers. Only one theory explains the effects of democratic age on the wide range of policy outcomes examined here-the inability of political competitors in younger democracies to make credible promises to citizens. This explanation, first advanced in Keefer and Vlaicu (2004), offers a concrete interpretation of what political institutionalization might mean, and why it is that young democracies frequently fail to become older and well-performing democracies. A variety of tests support this explanation against alternatives. The effect of democratic age remains large even after controlling for the possibilities that voters are less well-informed in young democracies, that young democracies have systematically different political and electoral institutions, or that young democracies exhibit more polarized societies.
{"title":"Democratization and Clientelism: Why are Young Democracies Badly Governed?","authors":"Philip Keefer","doi":"10.1596/1813-9450-3594","DOIUrl":"https://doi.org/10.1596/1813-9450-3594","url":null,"abstract":"This paper identifies systematic performance differences between younger and older democracies: younger democracies are more corrupt; exhibit less rule of law, lower levels of bureaucratic quality, and lower secondary school enrollments; and spend more on public investment and government workers. Only one theory explains the effects of democratic age on the wide range of policy outcomes examined here-the inability of political competitors in younger democracies to make credible promises to citizens. This explanation, first advanced in Keefer and Vlaicu (2004), offers a concrete interpretation of what political institutionalization might mean, and why it is that young democracies frequently fail to become older and well-performing democracies. A variety of tests support this explanation against alternatives. The effect of democratic age remains large even after controlling for the possibilities that voters are less well-informed in young democracies, that young democracies have systematically different political and electoral institutions, or that young democracies exhibit more polarized societies.","PeriodicalId":163698,"journal":{"name":"Institutional & Transition Economics eJournal","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126575623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Yukos affair, a high-profile story of the state-led assault on a private Russian company, provides an excellent opportunity for an inquiry into the nature of company-specific political risks in emerging markets. News associated primarily with law enforcement agencies’ actions against company’s managers, not formally related to the company itself, caused significant negative abnormal returns for Yukos. The results are robust and not driven by a few major events, such as the arrests of Yukos’ top managers and shareholders. Stocks of less transparent private Russian companies have been more sensitive to Yukos-related events, especially employee-related charges by law enforcement agencies. The situation was different for less transparent government-owned companies such as the world-largest natural gas producer Gazprom: they appear to be significantly less sensitive to these events. Actions of regulatory agencies have had predominantly industry-wide impact, whereas law-enforcement agencies’ actions affected shares of large private companies, especially those privatized in the notorious loans-for-shares privatization auctions.
{"title":"Is Political Risk Company-Specific? The Market Side of the Yukos Affair","authors":"Alexei P. Goriaev, K. Sonin","doi":"10.2139/ssrn.676875","DOIUrl":"https://doi.org/10.2139/ssrn.676875","url":null,"abstract":"The Yukos affair, a high-profile story of the state-led assault on a private Russian company, provides an excellent opportunity for an inquiry into the nature of company-specific political risks in emerging markets. News associated primarily with law enforcement agencies’ actions against company’s managers, not formally related to the company itself, caused significant negative abnormal returns for Yukos. The results are robust and not driven by a few major events, such as the arrests of Yukos’ top managers and shareholders. Stocks of less transparent private Russian companies have been more sensitive to Yukos-related events, especially employee-related charges by law enforcement agencies. The situation was different for less transparent government-owned companies such as the world-largest natural gas producer Gazprom: they appear to be significantly less sensitive to these events. Actions of regulatory agencies have had predominantly industry-wide impact, whereas law-enforcement agencies’ actions affected shares of large private companies, especially those privatized in the notorious loans-for-shares privatization auctions.","PeriodicalId":163698,"journal":{"name":"Institutional & Transition Economics eJournal","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127560219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-04-14DOI: 10.1111/j.1475-679X.2005.00187.x
James R. Frederickson, W. Waller
A fundamental management accounting issue is how to incorporate decision-influencing information (e.g., an ex post state signal) into employment contracts. Our experiment examines the effects of contract framing on such information use in a principal-agent setting. In each of 40 rounds, participants (as employer and worker) negotiate a contract that specifies pay depending on an ex post state signal. State-signal pay is framed as either a bonus or a penalty over two groups. The results show that the bonus frame facilitates information use, because of worker loss aversion. Although both groups initially underweigh the state signal, the bonus group quickly converges toward the optimal weight, whereas the penalty group persistently underweighs the state signal.
{"title":"Carrot or Stick? Contract Frame and Use of Decision-Influencing Information in a Principal-Agent Setting","authors":"James R. Frederickson, W. Waller","doi":"10.1111/j.1475-679X.2005.00187.x","DOIUrl":"https://doi.org/10.1111/j.1475-679X.2005.00187.x","url":null,"abstract":"A fundamental management accounting issue is how to incorporate decision-influencing information (e.g., an ex post state signal) into employment contracts. Our experiment examines the effects of contract framing on such information use in a principal-agent setting. In each of 40 rounds, participants (as employer and worker) negotiate a contract that specifies pay depending on an ex post state signal. State-signal pay is framed as either a bonus or a penalty over two groups. The results show that the bonus frame facilitates information use, because of worker loss aversion. Although both groups initially underweigh the state signal, the bonus group quickly converges toward the optimal weight, whereas the penalty group persistently underweighs the state signal.","PeriodicalId":163698,"journal":{"name":"Institutional & Transition Economics eJournal","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"119025521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is acknowledged that the lack of any systematic link between growth and income inequality does not necessarily mean that economic growth is not accompanied by major changes in the underlying income distribution. The author uses a method devised to decompose the redistributive effect of a tax to analyze the extent to which vertical redistribution associated with changing incomes over time is offset or reinforced by horizontal redistribution and re-ranking. He uses panel data from China and Vietnam over a period when both countries grew spectacularly as they transitioned from planned to market economies, and yet experienced smaller annual percentage increases in income inequality. The results suggest that substantial amounts of horizontal redistribution and re-ranking in both China-and to a lesser extent Vietnam-more than offset pro-poor vertical redistribution. Without the horizontal redistribution and re-ranking, the Gini coefficient for China might have fallen between 1989 and 1997-substantially so.
{"title":"Decomposing Changes in Income Inequality into Vertical and Horizontal Redistribution and Reranking, with Applications to China and Vietnam","authors":"A. Wagstaff","doi":"10.1596/1813-9450-3559","DOIUrl":"https://doi.org/10.1596/1813-9450-3559","url":null,"abstract":"It is acknowledged that the lack of any systematic link between growth and income inequality does not necessarily mean that economic growth is not accompanied by major changes in the underlying income distribution. The author uses a method devised to decompose the redistributive effect of a tax to analyze the extent to which vertical redistribution associated with changing incomes over time is offset or reinforced by horizontal redistribution and re-ranking. He uses panel data from China and Vietnam over a period when both countries grew spectacularly as they transitioned from planned to market economies, and yet experienced smaller annual percentage increases in income inequality. The results suggest that substantial amounts of horizontal redistribution and re-ranking in both China-and to a lesser extent Vietnam-more than offset pro-poor vertical redistribution. Without the horizontal redistribution and re-ranking, the Gini coefficient for China might have fallen between 1989 and 1997-substantially so.","PeriodicalId":163698,"journal":{"name":"Institutional & Transition Economics eJournal","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125847282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent Eurobarometer survey data are used to document and explain the stock of social capital in 27 European countries. Social capital in Central and Eastern Europe – measured by civic participation and access to social networks – lags behind that in Western European countries. Using regression analysis of determinants of individual stock of social capital, we find that this gap persists when we account for individual characteristics and endowments of respondents but disappears completely after we control for aggregate measures of economic development and quality of institutions. Informal institutions such as prevalence of corruption appear particularly important.
{"title":"Formation of Social Capital in Central and Eastern Europe: Understanding the Gap Vis-a-Vis Developed Countries","authors":"J. Fidrmuc, K. Gërxhani","doi":"10.2139/ssrn.729324","DOIUrl":"https://doi.org/10.2139/ssrn.729324","url":null,"abstract":"Recent Eurobarometer survey data are used to document and explain the stock of social capital in 27 European countries. Social capital in Central and Eastern Europe – measured by civic participation and access to social networks – lags behind that in Western European countries. Using regression analysis of determinants of individual stock of social capital, we find that this gap persists when we account for individual characteristics and endowments of respondents but disappears completely after we control for aggregate measures of economic development and quality of institutions. Informal institutions such as prevalence of corruption appear particularly important.","PeriodicalId":163698,"journal":{"name":"Institutional & Transition Economics eJournal","volume":"130 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132156582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
textabstractLikelihoods and posteriors of instrumental variable regression models with strong endogeneity and/or weak instruments may exhibit rather non-elliptical contours in the parameter space. This may seriously affect inference based on Bayesian credible sets. When approximating such contours using Monte Carlo integration methods like importance sampling or Markov chain Monte Carlo procedures the speed of the algorithm and the quality of the results greatly depend on the choice of the importance or candidate density. Such a density has to be `close' to the target density in order to yield accurate results with numerically efficient sampling. For this purpose we introduce neural networks which seem to be natural importance or candidate densities, as they have a universal approximation property and are easy to sample from. A key step in the proposed class of methods is the construction of a neural network that approximates the target density accurately. The methods are tested on a set of illustrative models. The results indicate the feasibility of the neural network approach.
{"title":"On the Shape of Posterior Densities and Credible Sets in Instrumental Variable Regression Models with Reduced Rank: An Application of Flexible Sampling Methods Using Neural Networks","authors":"Lennart F. Hoogerheide, J. Kaashoek, H. V. Dijk","doi":"10.2139/ssrn.878266","DOIUrl":"https://doi.org/10.2139/ssrn.878266","url":null,"abstract":"textabstractLikelihoods and posteriors of instrumental variable regression models with strong\u0000endogeneity and/or weak instruments may exhibit rather non-elliptical contours in\u0000the parameter space. This may seriously affect inference based on Bayesian credible\u0000sets. When approximating such contours using Monte Carlo integration methods like\u0000importance sampling or Markov chain Monte Carlo procedures the speed of the algorithm\u0000and the quality of the results greatly depend on the choice of the importance or\u0000candidate density. Such a density has to be `close' to the target density in order to\u0000yield accurate results with numerically efficient sampling. For this purpose we \u0000introduce neural networks which seem to be natural importance or candidate densities, \u0000as they have a universal approximation property and are easy to sample from.\u0000A key step in the proposed class of methods is the construction of a neural network \u0000that approximates the target density accurately. The methods are tested on a set of\u0000illustrative models. The results indicate the feasibility of the neural network\u0000approach.","PeriodicalId":163698,"journal":{"name":"Institutional & Transition Economics eJournal","volume":"10 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116655576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：