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   139894篇
  免费   3995篇
  国内免费   1篇
财政金融   26471篇
工业经济   11304篇
计划管理   22642篇
经济学   30937篇
综合类   1515篇
运输经济   1015篇
旅游经济   2539篇
贸易经济   23664篇
农业经济   6236篇
经济概况   17245篇
信息产业经济   8篇
邮电经济   314篇
  2021年   902篇
  2020年   1742篇
  2019年   2508篇
  2018年   2635篇
  2017年   2869篇
  2016年   2957篇
  2015年   2211篇
  2014年   3540篇
  2013年   15855篇
  2012年   4405篇
  2011年   4419篇
  2010年   3947篇
  2009年   4550篇
  2008年   4068篇
  2007年   3421篇
  2006年   3659篇
  2005年   3653篇
  2004年   3175篇
  2003年   2983篇
  2002年   2903篇
  2001年   2754篇
  2000年   2655篇
  1999年   2552篇
  1998年   2414篇
  1997年   2447篇
  1996年   2300篇
  1995年   2085篇
  1994年   2084篇
  1993年   2049篇
  1992年   2120篇
  1991年   1951篇
  1990年   1799篇
  1989年   1614篇
  1988年   1544篇
  1987年   1569篇
  1986年   1638篇
  1985年   2408篇
  1984年   2325篇
  1983年   2102篇
  1982年   1953篇
  1981年   1950篇
  1980年   1897篇
  1979年   1818篇
  1978年   1623篇
  1977年   1598篇
  1976年   1373篇
  1975年   1249篇
  1974年   1170篇
  1973年   1153篇
  1972年   868篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Growing urbanisation in South Africa is reflected in burgeoning Working class and informal township settlements on the fringes of its major towns and cities. Paired with this is an increasing reliance on cash as the primary means of economic transaction, which has in turn stimulated the growth of micro-enterprise business activities within the township context. This article discusses the findings of an eight-township small-area census which occurred between 2010 and 2013 in Cape Town, Johannesburg, Ekurhuleni and Durban townships representing 250 000 residents. The researchers were able to establish the scope and scale of informal food and drink retailing in these localities. Of the 10 049 micro-enterprises located in the study, some 3966 (or 39% of the total) trade in food. These include enterprises in primary production, fresh produce retailing, grocery retailing from house and spaza shops, and informal foodservice enterprises. Food is the basis for much township informal business and plays an important role in making food increasingly affordable and locally accessible, and in creating cash employment. The article builds on the knowledge base of the township informal economy role in bolstering food security needs for the marginalised.  相似文献   
22.
Without guaranteed compensation, granted by the German Renewable Energy Sources Act (Erneuerbare Energien Gesetz/EEG), biogas plants compete with all other plant types on the market for electrical energy. However, exchange-based electricity products do not currently permit an economically viable operation of biogas plants owing to their cost situation.  相似文献   
23.
24.
Objective: This study was to determine if calcium fortification yields a higher price per serving in grocery store products. Researchers compared store brand to national brand grocery products in relation to cost in order to examine if calcium values were similar between store brand and national brand products. Methods: A total of 112 store brand and 211 national brand grocery products were collected from three low (national chain store), middle and high priced (Virginia and North Carolina regional store) grocery venues. Products were compared using price and calcium percentage per serving. ANOVA was used to determine between store brand and national brand for price per serving and calcium content, and between grocery venues. Results: National brand fortified products had a significantly lower mean price per serving when compared to national brand non-fortified products (p = 0.0002). There was no statistical difference between store brand fortified and non-fortified products (p = 0.9256). Low priced store brand products had the lowest mean price per serving ($0.34 ±0.24). Conclusions: This study found store brand products have similar calcium content as national brand products. Product cost was lower at low priced store compared to middle and high priced stores.  相似文献   
25.
Consumer “multihoming” (watching two TV channels, or buying two news magazines) has surprisingly important effects on market equilibrium and performance in (two‐sided) media markets. We show this by introducing consumer multihoming and advertising finance into the classic circle model of product differentiation. When consumers multihome (attend more than one platform), media platforms can charge only incremental value prices to advertisers. Entry or merger leaves consumer prices unchanged under consumer multihoming, but leaves advertiser prices unchanged under single‐homing: Multihoming flips the side of the market on which platforms compete. In contrast to standard circle results, equilibrium product variety can be insufficient under multihoming.  相似文献   
26.
In this paper, we study consumers with limited memory and examine the effects of their price categorization on the pricing strategies of competing firms. The valuations of consumers are assumed to be heterogeneous. We find that it is possible to observe price dispersion even when each firm charges a single price if the consumers categorize prices non‐optimally. Moreover, we demonstrate that the likelihood of a price dispersion outcome is reduced when consumers with limited memory set up the price categories optimally. These findings suggest that the consumers' limited memory and their sub‐optimal behavior, that is, their inability to choose price categories optimally can be a reason for observed price dispersion.  相似文献   
27.
Kremer and Snyder (Q J Econ 130:1167–1239, 2015) show that demand curves for a preventive and treatment may have different shapes though they target the same disease, biasing the pharmaceutical manufacturer toward developing the lucrative rather than the socially desirable product. This paper tightens the theoretical bounds on the potential deadweight loss from such biases. Using a calibration of the global demand for HIV pharmaceuticals, we demonstrate the dramatically sharper analysis achievable with the new bounds, allowing us to pinpoint potential deadweight loss at 62% of the global gain from curing HIV. We use the calibration to perform policy counterfactuals, assessing welfare effects of government policies such as a subsidy, reference pricing, and price-discrimination ban. The fit of our calibration is good: we find that a hypothetical drug monopolist would price an HIV drug so high that only 4% of the infected population worldwide would purchase, matching actual drug prices and quantities in the early 2000s before subsidies in low-income countries ramped up.  相似文献   
28.
29.
We study the effect of the educational diversity of managers on the performance of team‐managed mutual funds using a large sample of U.S. equity funds from 1994 to 2013. We consider diversity in terms of both final educational degree and field of educational specialisation. We find that, in general, both types of diversity have a positive impact on fund performance, and our results are robust over a wide range of performance metrics and changes in market conditions.  相似文献   
30.
Abstract

Traditional warranty analysis focuses on the reliability of a product and offers warranty designs that compensate a consumer if the item fails. We introduce the concept of a performance-based warranty (PBW) that guarantees that a product will operate at or above some baseline level of performance, such as a minimum energy efficiency for an appliance. We illustrate how consumer behavior can change in the presence of a PBW and define the parameters for which a manufacturer may increase revenue. Finally, we present an algorithm to solve for the optimal PBW design given a consumer’s belief about the expected performance of the product.  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