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   3216篇
  免费   76篇
财政金融   568篇
工业经济   199篇
计划管理   548篇
经济学   702篇
综合类   43篇
运输经济   25篇
旅游经济   34篇
贸易经济   494篇
农业经济   170篇
经济概况   508篇
信息产业经济   1篇
  2021年   33篇
  2020年   56篇
  2019年   62篇
  2018年   74篇
  2017年   86篇
  2016年   100篇
  2015年   42篇
  2014年   101篇
  2013年   395篇
  2012年   119篇
  2011年   146篇
  2010年   111篇
  2009年   99篇
  2008年   99篇
  2007年   105篇
  2006年   70篇
  2005年   59篇
  2004年   52篇
  2003年   52篇
  2002年   52篇
  2001年   56篇
  2000年   38篇
  1999年   47篇
  1998年   38篇
  1997年   46篇
  1996年   43篇
  1995年   34篇
  1994年   52篇
  1993年   36篇
  1992年   40篇
  1991年   31篇
  1990年   40篇
  1989年   37篇
  1988年   42篇
  1987年   35篇
  1986年   26篇
  1985年   54篇
  1984年   47篇
  1983年   36篇
  1982年   53篇
  1981年   39篇
  1980年   46篇
  1979年   41篇
  1978年   47篇
  1977年   32篇
  1976年   32篇
  1975年   38篇
  1974年   23篇
  1973年   30篇
  1971年   26篇
排序方式: 共有3292条查询结果,搜索用时 15 毫秒
871.
Supplying our world's growing nutrition needs in more sustainable ways has become an urgent global imperative, given the constraints of finite resources and the challenges of accelerating climate change. We present national-level eco-efficiency metrics in several representative production countries during the most recent decade (2000–2010) for four important crops: canola, cotton, maize, and soybeans. The metrics address greenhouse gas emissions and the utilization of land, water, and energy – all calculated per unit of production. We group countries based on their level of agricultural intensification and find that high-intensification countries are achieving the highest and yet still increasing levels of eco-efficiency, with these decadal gains: canola (26%), cotton (23%), maize (17%), and soybeans (18%). By stark contrast, low-intensification countries had no change in eco-efficiency during this same decade. Overall, our results suggest large opportunities for additional improvements in the developing world, and that cumulative resource savings through intensification have been significant. For instance, in the case of irrigated maize, if the high- and medium-intensification production countries had only achieved the same irrigation water-use efficiency as in the low-intensification countries, approximately 4 quadrillion (4×1015) more litres of irrigation water would have been consumed during the period 2000–2010.  相似文献   
872.
Abstract

This study analyzes Chinese consumer behavior across different retail food store formats and how household demographics affect shopping behavior. A multivariate probit model with four categories of retail food store formats (wet markets, small grocery stores, supermarkets, and hypermarkets) in Quindao, China is estimated. The results indicate that the new hypermarkets are substitutes for supermarkets, but they do not compete extensively with wet markets and small grocery stores. Furthur development of various catagories of food shopping store formats is linked to store-owner characteristics, potential interrelations among existing retail formats, as well as consumers' demographics and shipping habits.  相似文献   
873.
ABSTRACT

This study determines the impact service quality on customer satisfaction in the school meal context. The empirical analysis reveals three dimensions of service quality (quality of food, atmosphere, and customer service), which have a high impact on customer satisfaction. A low level of satisfaction was identified but with differences between the various schools. Understanding the antecedents of pupils' satisfaction is important to policy makers, schools, and school meals providers. Due to the increasing importance of school meal programs and their high impact on nutritional status on young people, a high service quality in school meal programs is inevitable.  相似文献   
874.
The aim of this paper is to assess the effects of accession to the EC on the UK agricultural input industries using a technique commonly applied to examining the effects of accession on the manufacturing sector, the main emphasis being on trade patterns. Some attempt is made to differentiate between the effects of market-widening and of the CAP, and an assessment of the welfare implications is given. The results indicate that the effect of market-widening on the input industries was more important than the effect of the CAP and that the net loss of trade diversion was slightly outweighed by the benefits of export expansion  相似文献   
875.
The aim of this article is to analyse one of the most traditional SME-support measures, the allocation of guarantees by the Spanish guarantee system. A counterfactual approach is adopted to evaluate the result of a public policy. Three groups of companies that constitute the casuistry of long-term financial supports to companies (guarantees, guarantees and preferential funding, or just preferential funding), as well as another two control groups are studied. The results suggest that public support is relevant at economic, financial and business efficiency levels. The advantages can be observed mainly in the weakest companies, where the capacity to tackle projects is facilitated, although they do not manage to reduce their financial costs until they reach relative levels similar to those reached by companies not accessing the guarantee system.  相似文献   
876.
This study examines the impact that research and development (R&D) intensity has on corporate social responsibility (CSR). We base our research on the resource-based view (RBV) theory, which contributes to our analysis of R&D intensity and CSR because this perspective explicitly recognizes the importance of intangible resources. Both R&D and CSR activities can create assets that provide firms with competitive advantage. Furthermore, the employment of such activities can improve the welfare of the community and satisfy stakeholder expectations, which might vary according to their prevailing environment. As expressions of CSR and R&D vary throughout industries, we extend our research by analysing the impact that R&D intensity has on CSR across both manufacturing and non-manufacturing industries. Our results show that R&D intensity positively affects CSR and that this relationship is significant in manufacturing industries, while a non-significant result was obtained in non-manufacturing industries.  相似文献   
877.
We discuss past work in the conceptualization and measurement of perceived service quality and describe the most important models proposed in the last 25 years. We infer the general equations that can be derived from each conceptualization. Finally, we summarize the shortcomings and contradictions of each model as well as conclusions reached so far by a certain consensus of researchers using different models. In order to provide a framework for understanding service quality models, we discuss the service quality paradigm from the realist and constructivist perspective along with the multidimensional nature of service quality implicit in the reflective versus formative debate. We conclude by recommending the development of more creative models of service quality, proposing three different options for quantitative analysis that minimize the various limitations that characterize the most widely used models.  相似文献   
878.
This study investigates the relationship between intention to behave ethically and gender within the context of national culture. Using Reidenbach and Robin's measures of the ethical dimensions of justice and utilitarianism in a sample of business students from three different countries, we found that gender is significantly related to the respondents' intention to behave ethically. Women relied on both justice as well as utilitarianism when making moral decisions. By contrast, men relied only on justice, and did not rely on utilitarianism when faced with the same ethical issues. Further, women's intention to behave was contextual, significantly affected by two national culture dimensions (uncertainty avoidance and individualism), whereas men's decisions were more universal, and not related to national culture dimensions.  相似文献   
879.
We conduct a comprehensive evaluation of the season‐average price projections for U.S. corn as published by the U.S. Department of Agriculture's World Agricultural Supply and Demand Estimates (WASDE), an important issue given reduced resources and increased program scrutiny within the Federal Government. This study is the first in the literature to evaluate the WASDE corn projections relative to futures adjusted forecasts throughout the forecasting cycle using a lengthy evaluation period (1980/81–2012/13). We find that WASDE projections provide lower RMSEs relative to futures adjusted forecasts for 9 of the 16 forecast periods, 4 of which are statistically different. Encompassing tests show that WASDE projections often provide incremental information not present in the futures adjusted forecasts. Composite forecasts based on futures adjusted forecasts and WASDE projections reduced the RMSEs over all forecast periods by an average 12–16%. Favorable average trading profits may be generated for some forecast months using WASDE projections. Overall, our results suggest that WASDE projections of the U.S. corn season‐average price provide useful information to the market and could enhance the efficiency of the agricultural sector.  相似文献   
880.
Savannas cover the greater part of Africa and Australia and almost half of South America and contribute to the livelihoods of more than 350 million people. With the intensification of land use during the second half of the 20th century, savannas have become increasingly degraded through bush encroachment as a consequence of increased grazing pressure. Research on rangeland dynamics, however, provides contradicting answers with regard to the causes and possible remedies of bush encroachment. In this article we present results from an application of a simulation-optimization model to the case of extensive rangeland management in South Africa. Our model differs from previous approaches in that it explicitly accounts for the influence of stochastic prices and rainfall on economically optimal management decisions. By showing the implications of neglecting price variation and stochasticity in rangeland models we provide new insights with regard to the determinants of bush encroachment and rangeland managers' economic return. We demonstrate that, in the case of South Africa, optimal rangeland management is likely to lead to bush encroachment that eventually makes livestock holding unprofitable. Yet, we identify the costs of fire management to be a limiting factor for managers to counteract bush encroachment and explore the impact of policy measures to reduce fire control costs on the ecological and economic sustainability of livestock holding.  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