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   5445篇
  免费   140篇
  国内免费   1篇
财政金融   1208篇
工业经济   453篇
计划管理   940篇
经济学   1043篇
综合类   80篇
运输经济   46篇
旅游经济   84篇
贸易经济   943篇
农业经济   304篇
经济概况   483篇
邮电经济   2篇
  2021年   29篇
  2020年   69篇
  2019年   87篇
  2018年   98篇
  2017年   96篇
  2016年   110篇
  2015年   66篇
  2014年   110篇
  2013年   644篇
  2012年   165篇
  2011年   175篇
  2010年   155篇
  2009年   176篇
  2008年   182篇
  2007年   161篇
  2006年   167篇
  2005年   138篇
  2004年   137篇
  2003年   147篇
  2002年   169篇
  2001年   133篇
  2000年   116篇
  1999年   135篇
  1998年   106篇
  1997年   106篇
  1996年   100篇
  1995年   96篇
  1994年   78篇
  1993年   82篇
  1992年   72篇
  1991年   65篇
  1990年   68篇
  1989年   61篇
  1988年   65篇
  1987年   60篇
  1986年   73篇
  1985年   91篇
  1984年   90篇
  1983年   87篇
  1982年   74篇
  1981年   76篇
  1980年   78篇
  1979年   58篇
  1978年   72篇
  1977年   82篇
  1976年   45篇
  1975年   48篇
  1974年   54篇
  1973年   36篇
  1972年   30篇
排序方式: 共有5586条查询结果,搜索用时 15 毫秒
991.
Research and development (R&D) is a key factor enabling firms to gather information, create knowledge and innovate. Although often seen as the preserve of goods-producing sectors, knowledge-intensive business services (KIBS) in particular also engage in R&D. In this paper, we are interested in understanding the determinants of R&D in KIBS. We address this question by exploring factors connected to R&D in KIBS, with attention to whether it is connected with internal capabilities or to establishments' openness. We show that KIBS' R&D is associated with internal capabilities, and that recourse to external R&D is part of a strategy of openness that complements internal capacity. We also suggest that KIBS's own view of R&D is aligned with R&D in the goods-producing sector, leading establishments in non-technological KIBS sectors to under-report R&D.  相似文献   
992.
Objective: To provide updated evidence on US trends in: market exclusivity periods (MEPs, time between brand-name drug launch and first generic competitors) for new molecular entities (NMEs); likelihood, timing and number of Hatch-Waxman Act Paragraph IV patent challenges; and generic drug penetration.

Methods: This study used IMS Health National Sales PerspectivesTM US data to calculate MEPs for the 288 NMEs experiencing initial generic entry between January 1995 and December 2014, the number of generic competitors for 12 months afterward (by level of annual sales prior to generic entry), and generic penetration rates. The likelihood, timing and number of Paragraph IV challengers were calculated using data from Abbreviated New Drug Approval (ANDA) letters, the FDA website, public information searches, and ParagraphFour.com.

Results: For drugs experiencing initial generic entry in 2013–2014, the MEP was 12.5 years for drugs with sales greater than $250 million (in 2008 dollars) in the year prior to generic entry ($250 million?+?NMEs), 13.6 years overall. After generic entry, brands rapidly lost sales, with their average unit share being 7% at 1 year for $250 million?+?NMEs, 12% overall. Ninety-four percent of $250 million?+?NMEs experiencing initial generic entry in 2013–2014 had faced at least one Paragraph IV challenge, an average of 5.2 years after brand launch (76% and 5.9 years for all NMEs). NMEs faced an average of 5.1 and 6.2 Paragraph IV challenges per NME, for all and $250 million?+?NMEs, respectively.

Limitations: Analyses, including Paragraph IV calculations, were restricted to NMEs where generic entry had occurred.

Conclusion: The average 2013–2014 MEP of 12.5 years for $250 million?+?NMEs, 13.6 overall remains consistent with prior research. MEPs are lower, and Paragraph IV challenges are more frequent and occur earlier for $250 million?+?drugs. Generic share erosion is also greater, and continues to intensify for both NME types.  相似文献   
993.
We examine the effects of biased (conservative or liberal) reporting on product market competition. Cournot duopolists observe either firm-specific or industry-wide shocks and provide noisy reports subject to an exogenous mandated bias attributed to public policy. Given neutral prior beliefs, either a conservative bias or a liberal bias enhances overall reporting-system informativeness as measured by the reduction of uncertainty. Consistent with previously established effects in the information sharing literature regarding increases in informativeness, we show that expected industry profits and expected consumer surplus may gain or lose from bias, depending on whether the shocks are firm-specific or industry-wide and the degree of product competition. Expected social welfare, however, always increases in bias, irrespective of the source of uncertainty and product substitutability or complementarity. We next consider a setting where firms self-select whether to bias reports and characterize regions of potential conflict with a public policy that maximizes expected social welfare. Further results on the differential effects of conservative or liberal bias follow from relaxing the assumption of neutral prior beliefs.  相似文献   
994.
This research tests whether Holderness Jr., D. K., Myers, N., Summers, S. L., & Wood, D. A. [(2014). Accounting education research: Ranking institutions and individual scholars. Issues in Accounting Education, 29(1), 87–115] accounting-education rankings are sensitive to a change in the set of journals used. It provides updated rankings for accounting-education authors from Australia, Canada, New Zealand, the Republic of Ireland, the United Kingdom, and the United States using a sample that included the publications in 13 accounting-education journals. Our analysis indicated that Holderness et al.’s rankings of authors and departments were significantly different from our rankings. This research provides rankings of the top 50 authors and departments for three periods: from 2010 to 2015, from 2004 to 2015, and from 1992 to 2015. We provide data indicating the distribution of authors for these periods to assist authors not listed in the most prolific lists in determining their relative ranking. Finally, we provide data on the distribution of journal choices for accounting-education publications for the authors from each country.  相似文献   
995.
This study considers the actions of worker health and safety representatives in coalmines in Queensland, where there is little evidence of the facilitating role of management previous studies have associated with the successful operation of worker representation in occupational health and safety. It examines how worker representatives deliver their pluralist representational role in a context characterised by essentially unitary thinking amongst their employers and the effectiveness of the strategies they use.  相似文献   
996.
997.
We study business cycle fluctuations in heterogeneous agent general equilibrium models featuring intensive and extensive margins of labor supply. A nonlinear mapping from time devoted to work to labor services generates operative extensive and intensive margins. Our model captures the salient features of the empirical distribution of hours worked, including how individuals transit within this distribution. We study how various specifications influence labor supply responses to aggregate technology shocks and find that abstracting from intensive margin adjustment can have large effects on the volatility of aggregate hours even if fluctuations along the intensive margin are small.  相似文献   
998.
In most macroeconomic models inflation tends to be harmful. In this article, we show that by simply changing the timing of production decisions by firms from “on demand” to “in advance,” some inflation can boost welfare as long as goods are sufficiently perishable. The main conclusion from this research is that by effectively hiding the strategic interaction between supply and demand, assuming production on demand is not without loss of generality.  相似文献   
999.
Quantal Response Equilibria for Extensive Form Games   总被引:1,自引:0,他引:1  
This article investigates the use of standard econometric models for quantal choice to study equilibria of extensive form games. Players make choices based on a quantal-choice model and assume other players do so as well. We define an agent quantal response equilibrium (AQRE), which applies QRE to the agent normal form of an extensive form game and imposes a statistical version of sequential rationality. We also define a parametric specification, called logit-AQRE, in which quantal-choice probabilities are given by logit response functions. AQRE makes predictions that contradict the invariance principle in systematic ways. We show that these predictions match up with some experimental findings by Schotter et al. (1994) about the play of games that differ only with respect to inessential transformations of the extensive form. The logit-AQRE also implies a unique selection from the set of sequential equilibria in generic extensive form games. We examine data from signaling game experiments by Banks et al. (1994) and Brandts and Holt (1993). We find that the logit-AQRE selection applied to these games succeeds in predicting patterns of behavior observed in these experiments, even when our prediction conflicts with more standard equilibrium refinements, such as the intuitive criterion. We also reexamine data from the McKelvey and Palfrey (1992) centipede experiment and find that the AQRE model can account for behavior that had previously been explained in terms of altruistic behavior. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
1000.
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