首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9287篇
  免费   632篇
  国内免费   11篇
财政金融   2377篇
工业经济   179篇
计划管理   1912篇
经济学   3361篇
综合类   142篇
运输经济   14篇
旅游经济   25篇
贸易经济   665篇
农业经济   482篇
经济概况   773篇
  2024年   1篇
  2023年   51篇
  2022年   44篇
  2021年   67篇
  2020年   326篇
  2019年   383篇
  2018年   228篇
  2017年   319篇
  2016年   217篇
  2015年   268篇
  2014年   621篇
  2013年   785篇
  2012年   893篇
  2011年   1194篇
  2010年   808篇
  2009年   631篇
  2008年   689篇
  2007年   743篇
  2006年   446篇
  2005年   285篇
  2004年   199篇
  2003年   170篇
  2002年   92篇
  2001年   56篇
  2000年   40篇
  1999年   51篇
  1998年   49篇
  1997年   71篇
  1996年   45篇
  1995年   27篇
  1994年   23篇
  1993年   14篇
  1992年   2篇
  1991年   4篇
  1989年   1篇
  1985年   26篇
  1984年   24篇
  1983年   16篇
  1982年   9篇
  1981年   2篇
  1980年   3篇
  1979年   1篇
  1978年   4篇
  1977年   1篇
  1975年   1篇
排序方式: 共有9930条查询结果,搜索用时 0 毫秒
141.
Crop management innovations are often not discrete fixed stand‐alone options—and their adoption may imply various combinations and adaptations. This potentially confounds their impact assessment. This article assesses the resource saving and productivity enhancing impacts of a crop management package revolving around minimum tillage in maize‐based farming systems in northwest Ethiopia. An endogenous switching regression model was applied to plot‐ and household‐level survey data collected from 290 rural households operating 590 maize plots during the 2012 production year. Controlling for variations in plot and household characteristics, the average effect of minimum tillage package (minimum tillage package) on maize productivity is 0.44 t/ha. Compared to conventional practice (CP), adoption of the MTP decreased the average male and female labor use in maize production by 14.4 and 8.2 person‐days per ha, respectively. Similarly, MTP adoption decreased draft power use for land preparation by 13.2 pair of oxen‐days per ha. Compared to CP, in general, there is a considerable short‐run maize productivity gain and reduction in labor and draft power use under MTP.  相似文献   
142.
This study revisits the issue of mean reversion in the import rice prices of six Asian countries over the period between 1995 and 2015. Augmented Dickey Fuller tests with a conventional linear regression model support the presence of a unit root in the levels of the price data. However, when regressions allow for Markov switching in coefficients and variances to capture periodic shifts in levels and volatilities, there is strong evidence against the unit‐root null hypothesis in favor of stationarity over much of the observation period.  相似文献   
143.
Improving student retention and academic performance is a key objective for higher education institutions, and finding effective interventions for assisting with at-risk students is therefore important. In this article, we evaluate a proactive pastoral care intervention that was trialled in an introductory economics course in New Zealand. We first identified students at high risk of failure, and then randomized these students into two treatment groups and a control group. The first treatment group received an email with information about academic support, while the second treatment group received the email as well as a personal telephone call to follow-up. In evaluating the impact of the intervention trial, we found that the first intervention did not significantly improve student outcomes, but the second intervention improved outcomes in one of the two semesters evaluated. Overall, the initiative was a qualified success. It is both simple and cost-effective and should be considered for wider implementation and further evaluation.  相似文献   
144.
There is growing interest in Nova Scotia's Environmental Farm Plan (NS EFP) program among farmers and policy makers because of several reasons. First, effectiveness of standardized or uniform beneficial management practices in mitigating the negative environmental impacts from agriculture is limited by inherent heterogeneities in agricultural production systems. In addition, there is heightened interest in farmers generating ecological goods and services to society. This study investigates the determinants of participation in the NS EFP program. A discrete choice model of NS EFP participation was applied to a sample of 83 farmers (representing a 31% response rate). To increase relevance of the study to program administrators, the study also examined farmers’ use of various channels and sources of information on farm conservation practices. The most used sources of information on farm conservation practices include a mix of interpersonal sources and government agencies. Although online information (especially those available for free) appears to be gaining popularity in usage, overall, electronic and computer channels of information (especially radio and television) were used less compared with traditional channels of communicating farm conservation information (such as newsletters and agricultural magazines). Regression analysis suggests that farm characteristics (i.e., farm type, farm size, farm income) and farmer capacity variables (i.e., specialized training and knowledge from EFP program information sessions and workshops, and on-farm stewardship demonstrations) were significant determinants of environmental farm planning.  相似文献   
145.
This article reviews recent developments in China’s agricultural domestic support policy, especially the transition from taxing farmers and agriculture to providing direct subsidies to grain production and purchased inputs. A model‐based quantitative analysis on the effects of these policy changes is presented. Simulation results suggest that recent policy changes have achieved the declared policy goals of increasing grain production and boosting farm income. Much of the increase in grain production and farm income can be attributed to higher per unit return to arable land, land reallocation to grain production and extra agricultural employment triggered by the policy changes. Based on the assumption that China’s public assistance to agriculture and farmers will continue and rise, two hypothetical future scenarios are simulated. Using all the support permitted under WTO de minimis limits with existing instruments, China’s policy will increase grain production, change trade patterns seemingly contrary to China’s comparative advantage, increase rural employment and significantly increase farm income (by more than 12%). If, however, decoupled instruments are applied to raise China’s agricultural domestic support to the same level, China’s agricultural production and trade will remain unchanged, rural employment remain stable, but farm income will be increased by nearly 15%.  相似文献   
146.
This study uses panel data to demonstrate two dimensions of land ownership: the distribution between households at a given time and changes within a household over time. We note that recognizing the latter dimension is only possible when analyzing rare long‐term panel data. We estimate a model for land ownership using a version of the correlated random effects estimator to uniquely identify the determinants of both dimensions amongst Kenyan smallholders. We find life cycle effects are a key determinant of both distributions, and identify important ways in which initial conditions such as inheritance and off‐farm income relate to the dynamics of ownership. We find that population density is a key determinant of differences between households, but also that a given household's land ownership is not affected in the short term as population density increases around them. Controlling for population density, households own more land when they are closer to road networks where the economic value of land is higher. We find important vulnerabilities for the land security of widows, but this vulnerability is geographically heterogeneous.  相似文献   
147.
This article analyzes the theoretical underpinnings of producer willingness to pay (WTP) for new inputs. In addition to conceptualizing the producer WTP function, we derive its comparative statics and show how these properties can be used to estimate quantities demanded or supplied and price elasticities. We also discuss implications of the comparative statics.  相似文献   
148.
This article analyses co‐movements in a wide group of commodity prices during the time period 1992–2010. Our methodological approach is based on the correlation matrix and the networks inside. Through this approach we are able to summarize global interaction and interdependence, capturing the existing heterogeneity in the degrees of synchronization between commodity prices. Our results produce two main findings: (a) we do not observe a persistent increase in the degree of co‐movement of the commodity prices in our time sample, however from mid‐2008 to the end of 2009 co‐movements almost doubled when compared with the average correlation; (b) we observe three groups of commodities which have exhibited similar price dynamics (metals, oil and grains, and oilseeds) and which have increased their degree of co‐movement during the sampled period.  相似文献   
149.
This paper explores farmers’ willingness to adopt genetically modified (GM) oilseed rape prior to its commercial release and estimates the ‘demand’ for the new technology. The analysis is based upon choice experiments with 202 German arable farmers. A multinomial probit estimation reveals that GM attributes such as gross margin, expected liability from cross pollination, or flexibility in returning to conventional oilseed rape significantly affect the likelihood of adoption. Neighbouring farmers’ attitudes towards GM cropping and a number of farmer and farm characteristics were also found to be significant determinants of prospective adoption. Demand simulations suggest that adoption rates are very sensitive to the profit difference between GM and non‐GM rape varieties. A monopolistic seed price would substantially reduce demand for the new technology. A monopolistic seed supplier would reap between 45% and 80% of the GM rent, and the deadweight loss of the monopoly would range between 15% and 30% of that rent. The remaining rent for farmers may be too small to outweigh possible producer price discounts resulting from the costs of segregating GM and non‐GM oilseed rape along the supply chain.  相似文献   
150.
We examine the impact of the end of the coffee export quota system (EQS) on international‐to‐retail price transmission in France, Germany and the United States. We take account of the existence of long‐run threshold effects and short‐run price transmission asymmetries (PTAs). We find evidence of threshold effects in both periods (EQS and post‐EQS) in all three countries and the presence of short‐run PTAs during the post‐EQS period in all countries, but not during the EQS period. Our results indicate that the threshold values are smaller in the post‐EQS period, suggesting that retail prices became more responsive to changes in international prices. However, the speed of adjustment towards the long‐run equilibrium decreases during the post‐EQS period in the three countries. In the short run, non‐linear impulse response analyses indicate that a shock in international prices was more persistent during the EQS period than in the post‐EQS period. Moreover, we find evidence of short‐run PTAs in the post‐EQS period, with differences across countries. We find support for the ‘rockets and feathers’ principle in the United States; in contrast, retail prices respond faster when international prices are falling in Germany and France. We explain these differences in terms of market structures.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号