Pub Date : 2021-09-01DOI: 10.30430/70.2021.3.165-181
W. Britz
{"title":"Automated calibration of farm-scale mixed linear programming models using bi-level programming","authors":"W. Britz","doi":"10.30430/70.2021.3.165-181","DOIUrl":"https://doi.org/10.30430/70.2021.3.165-181","url":null,"abstract":"","PeriodicalId":48919,"journal":{"name":"German Journal of Agricultural Economics","volume":"28 1","pages":"165-181"},"PeriodicalIF":0.5,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85636013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-01DOI: 10.30430/70.2021.3.192-207
Insa Thiermann, G. Breustedt, Uwe Latacz-Lohmann
{"title":"Verringerung von Ammoniakemissionen durch Gülleansäuerung auf dem Feld: Teilnahmebereitschaft von Landwirten an Förderprogrammen","authors":"Insa Thiermann, G. Breustedt, Uwe Latacz-Lohmann","doi":"10.30430/70.2021.3.192-207","DOIUrl":"https://doi.org/10.30430/70.2021.3.192-207","url":null,"abstract":"","PeriodicalId":48919,"journal":{"name":"German Journal of Agricultural Economics","volume":"16 1","pages":"192-207"},"PeriodicalIF":0.5,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73633971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-01DOI: 10.30430/70.2021.2.84-100
K. Fischer, S. Hess
Swedish farmers were surveyed about their perceptions of genetically modified (GM) feed. Livestock in the EU are frequently given feed containing imported genetically modified (GM) crops, with GM fodder often being cheaper for farmers. However, there is also a growing market for ‘GM-free’ animal-based products. While public concerns about GMOs have been studied extensively, less is known about farmers’ views. The limited literature on farmers and GMOs tends to focus on the economic factors influencing their adoption. The present study contributes the perspective of farmers as members of the general public, thus including a broader set of factors known to be relevant for the public perception of GMOs. The results indicated that farmers were worried about: i) unforeseen consequences for the environment, ii) unforeseen consequences for human and animal health, and iii) the dominance of multinational companies. Farmers who could expect their farm businesses to benefit from existing GMOs were more positive, whereas those who were unlikely to experience any benefits or who could expect their farm business to be adversely affected were more negative. Nevertheless, adherence to a broader set of positive or negative values suggests that Swedish farmers’ perspectives on GMOs go further than pure considerations of farm management.
{"title":"Beyond Cost Minimisation: Farmers’ Perspectives on the Adoption of GM Fodder in Sweden","authors":"K. Fischer, S. Hess","doi":"10.30430/70.2021.2.84-100","DOIUrl":"https://doi.org/10.30430/70.2021.2.84-100","url":null,"abstract":"Swedish farmers were surveyed about their perceptions of genetically modified (GM) feed. Livestock in the EU are frequently given feed containing imported genetically modified (GM) crops, with GM fodder often being cheaper for farmers. However, there is also a growing market for ‘GM-free’ animal-based products. While public concerns about GMOs have been studied extensively, less is known about farmers’ views. The limited literature on farmers and GMOs tends to focus on the economic factors influencing their adoption. The present study contributes the perspective of farmers as members of the general public, thus including a broader set of factors known to be relevant for the public perception of GMOs. The results indicated that farmers were worried about: i) unforeseen consequences for the environment, ii) unforeseen consequences for human and animal health, and iii) the dominance of multinational companies. Farmers who could expect their farm businesses to benefit from existing GMOs were more positive, whereas those who were unlikely to experience any benefits or who could expect their farm business to be adversely affected were more negative. Nevertheless, adherence to a broader set of positive or negative values suggests that Swedish farmers’ perspectives on GMOs go further than pure considerations of farm management.","PeriodicalId":48919,"journal":{"name":"German Journal of Agricultural Economics","volume":"46 1","pages":"84-100"},"PeriodicalIF":0.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81416095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-01DOI: 10.30430/70.2021.2.70-83
Christian Sponagel, Hans Back, E. Angenendt, E. Bahrs
Impacts on nature and landscape are to be offset in accordance with different nature conservation acts in various European countries. In Germany in particular, biodiversity offsets can also be made in advance, for instance, by booking them into eco-accounts, and then allocating them to an intervention. In Baden-Württemberg, these offset measures are assessed in eco credits in accordance with the Eco Account Regulation (ÖKVO). As a means of income diversification, farmers can voluntarily implement offset measures on their land, and then generate and sell corresponding eco credits. Using a geodata-based model, the potential for implementing biodiversity offsets on arable land – areas with major eco credit potential – is analysed from an economic perspective. The Stuttgart Region is a steadily growing conurbation in south-west Germany. It serves as a study region since the loss of farmland due to large-scale construction measures and the related offsetting are a major issue here. In the analysis, the gross margins of the crops grown, their yield capacity, the associated standard land values and the costs of possible offset measures are used to determine the net present value of the arable land at parcel level. From a theoretical point of view and depending on the market price for eco credits, there is a significant potential for offset measures on arable land. Production-integrated compensation (PIC) – an extensification of arable land use – is less economically viable than the conversion of arable land into grassland or its utilisation for nature conservation. There are major spatial disparities between the city of Stuttgart and the surrounding districts. The implementation of biodiversity offsets is not economically viable at a price of less than € 1.00 per eco credit in the city of Stuttgart. By contrast, in surrounding districts, offset measures may be economically viable and implemented on a large scale for less than € 0.30. This is particularly relevant as the districts concerned are located in the same natural area as the city of Stuttgart and the eco credits can, therefore, be attributed in the event of interventions. Based on derived supply curves, decision-makers can see the scale of additional costs of biodiversity offset measures if they are implemented in a spatially restricted region. The analyses presented here can help decision-makers to more easily weigh up the desired natural characteristics and economic effects in the context of agricultural land.
{"title":"Development of Supply Curves for Biodiversity Offsets on Agricultural Land – a Case Study from the Stuttgart Region","authors":"Christian Sponagel, Hans Back, E. Angenendt, E. Bahrs","doi":"10.30430/70.2021.2.70-83","DOIUrl":"https://doi.org/10.30430/70.2021.2.70-83","url":null,"abstract":"Impacts on nature and landscape are to be offset in accordance with different nature conservation acts in various European countries. In Germany in particular, biodiversity offsets can also be made in advance, for instance, by booking them into eco-accounts, and then allocating them to an intervention. In Baden-Württemberg, these offset measures are assessed in eco credits in accordance with the Eco Account Regulation (ÖKVO). As a means of income diversification, farmers can voluntarily implement offset measures on their land, and then generate and sell corresponding eco credits. Using a geodata-based model, the potential for implementing biodiversity offsets on arable land – areas with major eco credit potential – is analysed from an economic perspective. The Stuttgart Region is a steadily growing conurbation in south-west Germany. It serves as a study region since the loss of farmland due to large-scale construction measures and the related offsetting are a major issue here. In the analysis, the gross margins of the crops grown, their yield capacity, the associated standard land values and the costs of possible offset measures are used to determine the net present value of the arable land at parcel level. From a theoretical point of view and depending on the market price for eco credits, there is a significant potential for offset measures on arable land. Production-integrated compensation (PIC) – an extensification of arable land use – is less economically viable than the conversion of arable land into grassland or its utilisation for nature conservation. There are major spatial disparities between the city of Stuttgart and the surrounding districts. The implementation of biodiversity offsets is not economically viable at a price of less than € 1.00 per eco credit in the city of Stuttgart. By contrast, in surrounding districts, offset measures may be economically viable and implemented on a large scale for less than € 0.30. This is particularly relevant as the districts concerned are located in the same natural area as the city of Stuttgart and the eco credits can, therefore, be attributed in the event of interventions. Based on derived supply curves, decision-makers can see the scale of additional costs of biodiversity offset measures if they are implemented in a spatially restricted region. The analyses presented here can help decision-makers to more easily weigh up the desired natural characteristics and economic effects in the context of agricultural land.","PeriodicalId":48919,"journal":{"name":"German Journal of Agricultural Economics","volume":"70 1","pages":"70-83"},"PeriodicalIF":0.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81784051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-01DOI: 10.30430/70.2021.5.23-46
Clara Mehlhose, Tim Knöpfel, Bernhard Brümmer, A. Spiller, G. Busch
{"title":"Der Markt für Milch und Milcherzeugnisse 2020","authors":"Clara Mehlhose, Tim Knöpfel, Bernhard Brümmer, A. Spiller, G. Busch","doi":"10.30430/70.2021.5.23-46","DOIUrl":"https://doi.org/10.30430/70.2021.5.23-46","url":null,"abstract":"","PeriodicalId":48919,"journal":{"name":"German Journal of Agricultural Economics","volume":"44 1","pages":"23-46"},"PeriodicalIF":0.5,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79520627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-01DOI: 10.30430/70.2021.5.13-22
Jakob Dehoust, E. Albrecht, Oliver Balkhausen
{"title":"World agricultural commodity markets in the marketing year 2020/21","authors":"Jakob Dehoust, E. Albrecht, Oliver Balkhausen","doi":"10.30430/70.2021.5.13-22","DOIUrl":"https://doi.org/10.30430/70.2021.5.13-22","url":null,"abstract":"","PeriodicalId":48919,"journal":{"name":"German Journal of Agricultural Economics","volume":"14 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90642076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-01DOI: 10.30430/70.2021.5.128-155
R. Klepper
Nach 2012/13 werden auch fur das Jahr 2013/14 Produktionsuberschusse am Zuckermarkt erwartet. Die Zuckererzeugung liegt voraussichtlich rund 4 Mio. t uber dem Bedarf, sodass die weltweiten Bestande weiter auf ein komfortables Niveau von rund 45 % des Verbrauches anwachsen werden. Die Bestande bilden damit ein so hohes Sicherheitspolster, wie wir es seit sechs Jahren nicht mehr sahen. Dies kann nicht ohne Wirkung auf die weitere Preisentwicklung bleiben. Bereits zum Jahreswechsel 2013/14 notierten die Zuckerpreise auf einem dreieinhalb Jahrestief. Der Trend rucklaufiger Preise wird sich zwar kaum weiter fortsetzen konnen, doch eine nachhaltige Erholung vor 2015 ist in Anbetracht der hohen Lagerbestande unwahrscheinlich. Trotz weltweit wachsender Erzeugung werden die wichtigen Exporteure, wie Brasilien, Indien, Thailand, Australien und Guatemala, ihre Positionen halten oder sogar ausbauen konnen. Dies ist erklartes Ziel ihrer Regierungen, gestutzt durch entsprechende Masnahmen dieser Lander. Diese Uberschusslander werden weiterhin die Versorgungslucke der Lander Afrikas und des Nahen und Mittleren Ostens sowie Teilen Asiens schliesen. Fur die EU, weiterhin ein stark geschutzter Wirtschaftsraum fur die Rubenanbauer und die Zuckerindustrie, wird erst die fur 2017 beschlossene Zuckermarktreform wesentliche Anderungen bringen. Noch profitieren die genannten Marktteilnehmer von hohen Zuckerpreisen bei eingeschranktem Wettbewerb. Die Marktversorgung ist durch die Quotenbindung und ausbleibende bzw. nicht ausreichende Importe aus den Praferenzabkommen schwach. Entsprechend hoch sind die Einstandspreise fur die Zuckerverarbeiter und Verbraucher. Die Zuckermuhlen und Rubenanbauer produzieren weiterhin proaktiv, was zu einem weiteren Anstieg der Zuckerbestande auch in der EU gefuhrt hat. Zumindest zum Jahresende 2013 ist eine leichte Annaherung der EU-Binnenmarktpreise an den Weltmarktpreis erkennbar. Ein Trend lasst sich daraus jedoch noch nicht ableiten. Die Rahmenbedingungen sind nach wie vor noch die gleichen. So sind die Zuckerpreise in der EU immer noch fast doppelt so hoch wie die Notierungen an den internationalen Borsen. Trotz des stark eingeschrankten Wettbewerbes scheinen die Haupterzeugerlander, allen voran Frankreich, ihre Positionen ausbauen zu konnen. Die leicht sinkenden Zuckerpreise in der EU und die nach Angaben der Zuckerindustrie hohen Beschaffungskosten haben nach einem Rekordjahr 2012/13 jedoch schon erste Spuren in den jungsten Bilanzen der (deutschen) Unternehmen im laufenden Wirtschaftsjahr hinterlassen. Der nach wie vor grose Preisabstand zu den Weltmarkten sollte auch auf absehbare Zeit Anreiz genug sein, die praferentiellen, grostenteils zollfreien Importe aus den Entwicklungs- und Transformationslandern in die EU zu befordern. Die im Jahr 2013 neu in Kraft getretenen Freihandelsabkommen mit mittel- und sudamerikanischen Staaten konnten ebenfalls dazu beitragen, dass die Zuckerpreise in der EU sinken. Ebenso das neue EU-Mitglied K
{"title":"Der Markt für Zucker","authors":"R. Klepper","doi":"10.30430/70.2021.5.128-155","DOIUrl":"https://doi.org/10.30430/70.2021.5.128-155","url":null,"abstract":"Nach 2012/13 werden auch fur das Jahr 2013/14 Produktionsuberschusse am Zuckermarkt erwartet. Die Zuckererzeugung liegt voraussichtlich rund 4 Mio. t uber dem Bedarf, sodass die weltweiten Bestande weiter auf ein komfortables Niveau von rund 45 % des Verbrauches anwachsen werden. Die Bestande bilden damit ein so hohes Sicherheitspolster, wie wir es seit sechs Jahren nicht mehr sahen. Dies kann nicht ohne Wirkung auf die weitere Preisentwicklung bleiben. Bereits zum Jahreswechsel 2013/14 notierten die Zuckerpreise auf einem dreieinhalb Jahrestief. Der Trend rucklaufiger Preise wird sich zwar kaum weiter fortsetzen konnen, doch eine nachhaltige Erholung vor 2015 ist in Anbetracht der hohen Lagerbestande unwahrscheinlich. Trotz weltweit wachsender Erzeugung werden die wichtigen Exporteure, wie Brasilien, Indien, Thailand, Australien und Guatemala, ihre Positionen halten oder sogar ausbauen konnen. Dies ist erklartes Ziel ihrer Regierungen, gestutzt durch entsprechende Masnahmen dieser Lander. Diese Uberschusslander werden weiterhin die Versorgungslucke der Lander Afrikas und des Nahen und Mittleren Ostens sowie Teilen Asiens schliesen. Fur die EU, weiterhin ein stark geschutzter Wirtschaftsraum fur die Rubenanbauer und die Zuckerindustrie, wird erst die fur 2017 beschlossene Zuckermarktreform wesentliche Anderungen bringen. Noch profitieren die genannten Marktteilnehmer von hohen Zuckerpreisen bei eingeschranktem Wettbewerb. Die Marktversorgung ist durch die Quotenbindung und ausbleibende bzw. nicht ausreichende Importe aus den Praferenzabkommen schwach. Entsprechend hoch sind die Einstandspreise fur die Zuckerverarbeiter und Verbraucher. Die Zuckermuhlen und Rubenanbauer produzieren weiterhin proaktiv, was zu einem weiteren Anstieg der Zuckerbestande auch in der EU gefuhrt hat. Zumindest zum Jahresende 2013 ist eine leichte Annaherung der EU-Binnenmarktpreise an den Weltmarktpreis erkennbar. Ein Trend lasst sich daraus jedoch noch nicht ableiten. Die Rahmenbedingungen sind nach wie vor noch die gleichen. So sind die Zuckerpreise in der EU immer noch fast doppelt so hoch wie die Notierungen an den internationalen Borsen. Trotz des stark eingeschrankten Wettbewerbes scheinen die Haupterzeugerlander, allen voran Frankreich, ihre Positionen ausbauen zu konnen. Die leicht sinkenden Zuckerpreise in der EU und die nach Angaben der Zuckerindustrie hohen Beschaffungskosten haben nach einem Rekordjahr 2012/13 jedoch schon erste Spuren in den jungsten Bilanzen der (deutschen) Unternehmen im laufenden Wirtschaftsjahr hinterlassen. Der nach wie vor grose Preisabstand zu den Weltmarkten sollte auch auf absehbare Zeit Anreiz genug sein, die praferentiellen, grostenteils zollfreien Importe aus den Entwicklungs- und Transformationslandern in die EU zu befordern. Die im Jahr 2013 neu in Kraft getretenen Freihandelsabkommen mit mittel- und sudamerikanischen Staaten konnten ebenfalls dazu beitragen, dass die Zuckerpreise in der EU sinken. Ebenso das neue EU-Mitglied K","PeriodicalId":48919,"journal":{"name":"German Journal of Agricultural Economics","volume":"17a 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88113800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-01DOI: 10.30430/70.2021.5.68-86
Christoph Frank Wiedenroth, Verena Otter
{"title":"Der Markt für Obst und Gemüse im Jahr 2020","authors":"Christoph Frank Wiedenroth, Verena Otter","doi":"10.30430/70.2021.5.68-86","DOIUrl":"https://doi.org/10.30430/70.2021.5.68-86","url":null,"abstract":"","PeriodicalId":48919,"journal":{"name":"German Journal of Agricultural Economics","volume":"76 1","pages":"68-86"},"PeriodicalIF":0.5,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84953553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-01DOI: 10.30430/70.2021.1.49-62
Jonas Peltner, Silke Thiele
This paper presents price and income elasticities of food demand for Germany. Using disaggregated household scanner data and the Quadratic Almost Ideal Demand System (QUAIDS). The QUAIDS is modified to account for censoring and include household demographics. Furthermore, a two-stage budgeting approach is used to more accurately reflect households’ purchasing behaviour. Having disaggregated data also allowed to include convenience aspects into the demand system. High expenditure elasticities are found for fruits and nuts and meat, fish and eggs. The highest own-price elasticity is found for beverages. At the second stage, the bread toppings group reveals new insights into demand relations between cold cuts, cheese and other spreads. Cold cuts have both the highest expenditure and own-price elasticity. Cross-price elasticities indicate mostly complementary relations between cold cuts and other bread toppings. Comparing different income groups shows that expenditure elasticities of raw foods or basic ingredient foods tend to decrease as income increases, whereas expenditure elasticities of foods that require minimal or no preparation tend to increase with income. In conclusion, this study stresses the need for regularly updated elasticities of food demand that reflect up-to-date consumption behavior.
{"title":"Elasticities of Food Demand in Germany – A Demand System Analysis Using Disaggregated Household Scanner Data","authors":"Jonas Peltner, Silke Thiele","doi":"10.30430/70.2021.1.49-62","DOIUrl":"https://doi.org/10.30430/70.2021.1.49-62","url":null,"abstract":"This paper presents price and income elasticities of food demand for Germany. Using disaggregated household scanner data and the Quadratic Almost Ideal Demand System (QUAIDS). The QUAIDS is modified to account for censoring and include household demographics. Furthermore, a two-stage budgeting approach is used to more accurately reflect households’ purchasing behaviour. Having disaggregated data also allowed to include convenience aspects into the demand system. High expenditure elasticities are found for fruits and nuts and meat, fish and eggs. The highest own-price elasticity is found for beverages. At the second stage, the bread toppings group reveals new insights into demand relations between cold cuts, cheese and other spreads. Cold cuts have both the highest expenditure and own-price elasticity. Cross-price elasticities indicate mostly complementary relations between cold cuts and other bread toppings. Comparing different income groups shows that expenditure elasticities of raw foods or basic ingredient foods tend to decrease as income increases, whereas expenditure elasticities of foods that require minimal or no preparation tend to increase with income. In conclusion, this study stresses the need for regularly updated elasticities of food demand that reflect up-to-date consumption behavior.","PeriodicalId":48919,"journal":{"name":"German Journal of Agricultural Economics","volume":"74 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86352502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","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：