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   8241篇
  免费   307篇
财政金融   1738篇
工业经济   710篇
计划管理   1331篇
经济学   1747篇
综合类   110篇
运输经济   95篇
旅游经济   163篇
贸易经济   1746篇
农业经济   243篇
经济概况   593篇
信息产业经济   4篇
邮电经济   68篇
  2023年   57篇
  2022年   47篇
  2021年   79篇
  2020年   121篇
  2019年   196篇
  2018年   218篇
  2017年   247篇
  2016年   215篇
  2015年   175篇
  2014年   276篇
  2013年   951篇
  2012年   311篇
  2011年   357篇
  2010年   325篇
  2009年   365篇
  2008年   324篇
  2007年   277篇
  2006年   254篇
  2005年   284篇
  2004年   236篇
  2003年   243篇
  2002年   234篇
  2001年   193篇
  2000年   174篇
  1999年   175篇
  1998年   146篇
  1997年   152篇
  1996年   125篇
  1995年   119篇
  1994年   125篇
  1993年   115篇
  1992年   109篇
  1991年   95篇
  1990年   66篇
  1989年   74篇
  1988年   68篇
  1987年   66篇
  1986年   67篇
  1985年   112篇
  1984年   89篇
  1983年   82篇
  1982年   89篇
  1981年   65篇
  1980年   73篇
  1979年   66篇
  1978年   57篇
  1977年   60篇
  1976年   55篇
  1974年   31篇
  1973年   20篇
排序方式: 共有8548条查询结果,搜索用时 15 毫秒
981.
982.
To solve the education “woes” of the U.S., many experts have looked to both command economies (standardized curriculum), and competitive markets (e.g. school choice and school vouchers), for answers. This normative research explores an optimal mix between market economies and command economies in education through the use of the business-format franchising structure. Franchising, an organizational form lying between the extremes of markets and hierarchies, would establish a standardized curriculum composed of those components of education that are deemed essential to the educational growth of our students. At the same time, franchising allows for levels of autonomy for educational institutions that would enable them to effectively target the additional needs and preferences of their local area, which in turn develops competitive markets in which schools compete for student enrollment thereby remedying the moral hazard problem. Finally, two additional characteristics that make this format attractive in tackling the problems in education are its continuous transfer of “know how” and its regular technical assistance. In the context of education, these characteristics translate into necessary links between educational theory and practice as well as national research and training grounds for teachers and administrators.  相似文献   
983.
984.
Cold treatment periods, and associated levels of quarantine security, that maximize net US welfare under USDA's current medfly detection and control program are examined using a deterministic bioeconomic optimization model . As anticipated, the efficient level of quarantine security is shown to increase with indices of medfly pressure (initial infestation rates) in areas in which the medfly is known to exist (the QCs) . Efficient cold treatment periods and weighted mean medfly survival rates are 8, 11, and 12 days and 5.0 × 10–2, 1.7 × 10–3, and 5.2 × 10–4 under low, moderate, and high initial infestation rates, respectively. When model output is averaged across initial infestation rates, an 11‐day cold treatment period, resulting in a weighted mean medfly survival rate of 1.6 × 10–3, maximizes US welfare. These findings suggest that the current minimum cold treatment period of 14 days and the current objective of US cold treatment policy—the probit 9 level of quarantine security—are economically inefficient. Adopting the 11‐day cold treatment period is shown to increase US social surplus by an annual $24.9 million, of which $21.5 and $3.4 million would accrue to US consumers and producers, respectively, and QC producer surplus by an annual $24.8 million. Nous avons examiné, à l’aide d’un modèle déterministe d’optimisation bioéconomique, les périodes de traitement par le froid et les niveaux de quarantaine de sécurité connexes qui maximisent le bien‐être net des États‐Unis d’après le programme actuel de détection et de lutte contre la cératite, instauré par le USDA. Comme prévu, le degré de quarantaine de sécurité efficace augmente en fonction des indices de pression des ravageurs (indices d’infestation initiale) dans les pays où la cératite est présente (pays dont les produits sont soumis à une quarantaine). Selon qu’il s’agit d’un indice d’infestation initiale faible, moyen et élevé, les périodes de traitement par le froid efficaces sont de 8, 11 et 12 jours respectivement et les taux de survie moyens pondérés de la cératite de 5,0 × 10–2, 1,7 × 10–3, et 5,2 × 10–4 respectivement. Lorsque l’on établit la moyenne pondérée de la sortie du modèle par taux de survie, une période de traitement de 11 jours et un taux de survie moyen pondéré de 1,6 × 10–3 maximisent le bien‐être des États‐Unis. Ces résultats donnent à penser que la période minimale actuelle de traitement par le froid de 14 jours et la politique actuelle concernant le traitement par le froid (la norme probit 9) sont économiquement inefficaces. L’adoption d’une période de traitement par le froid de 11 jours augmenterait le surplus collectif des États‐Unis de 24,9 millions (M$) par année, dont 21,5 M$ et 3,4 M$ reviendraient aux consommateurs et aux producteurs des États‐Unis respectivement, et un surplus de 24,8 M$ par année aux producteurs des pays dont les produits sont soumis à une quarantaine.  相似文献   
985.
986.
Natural resource accounting in theory and practice: A critical assessment   总被引:1,自引:0,他引:1  
In this paper an extensive review of the theoretical and applied literature on natural resource accounting (NRA) is provided. The review begins by explaining the economic theory that underpins NRA, contrasting welfare and sustainability as policy goals, and presenting various distinct conceptions of national income. The state of play regarding official revisions to the system of national accounts (SNA) with respect to natural resources and the environment is presented and controversial areas are highlighted. Finally, the economic literature on proposed revisions, and applied studies that have proceeded using these methods, is summarised and critiqued. We argue that much of the literature proceeds with weak conceptual foundations, and that typical case studies produce results that are ambiguous in interpretation. Moreover, we highlight fundamental tensions between economic theory and national accounting methodology, and conclude that one outcome of this has been the insufficient attention paid by economists to the revisions to the SNA; instead devoting time and effort to 'freelance' NRA case studies utilising sometimes ad hoc methods from the economic literature.  相似文献   
987.
Risk, uncertainty, and learning in adoption of a crop innovation   总被引:1,自引:0,他引:1  
Risk and uncertainty have often been suggested as causes of poor adoption of rural innovations, but empirical evidence has been scarce. This study focuses on a new crop‐type, chickpeas, in Western Australia to gather such evidence. The empirical models developed are based on a theoretical framework that conceptualizes adoption as a dynamic decision process involving information acquisition and learning‐by‐doing by growers who vary in their managerial abilities, risk preferences, and their perceptions of the profitability and riskiness of the innovation. Learning encompasses improvements in skill as well as reductions in uncertainty. An annual face‐to‐face survey of over 100 farmers was conducted over 3 years, eliciting the farmers' risk attitudes and their subjective distributions of yields and prices. Two limited dependent variable models, Tobit and Probit, are used to estimate the empirical model. There is a high degree of goodness‐of‐fit for both models. The study provides strong empirical support for the primarily economic character of the adoption decision, and highlight the importance of economic risk in the process. The two risk‐related factors with greatest impact on the adoption decision were risk aversion and relative riskiness of the innovation. Risk aversion tended to reduce adoption, and to do so to a greater extent as relative riskiness and scale increased. Results also reveal the key role that trialing of the innovation plays in adoption.  相似文献   
988.
989.
Technology choice under changing peanut policies   总被引:2,自引:0,他引:2  
The effect of marketing quotas and price supports on technology adoption are examined for peanut production in the southeastern United States using a real options model of investment with output price and yield uncertainty. The optimal choice of peanut production technology (dryland versus irrigated) in the southeast is shown to depend on price supports and how they change. The manner in which price supports change will have an effect on the choice and rates of abandonment or adoption of production technologies.  相似文献   
990.
Beefpacking underwent a dramatic transformation in the 1970s and 1980s, as plants got much larger and industry concentration rose dramatically. We use individual Census Bureau plant records to analyze the sources of the transformation. We find that there were modest but extensive scale economies in packing plants, covering the full range of plant sizes, and that such economies became more important throughout the period of the study. As production shifted to larger plants, we estimate that the industry's aggregate processing costs fell by 35.3% by 2002, compared to what they would have been without consolidation.  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