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   134048篇
  免费   3845篇
  国内免费   2篇
财政金融   25282篇
工业经济   11523篇
计划管理   21295篇
经济学   28539篇
综合类   1443篇
运输经济   952篇
旅游经济   2480篇
贸易经济   23250篇
农业经济   6049篇
经济概况   16837篇
信息产业经济   7篇
邮电经济   238篇
  2021年   828篇
  2020年   1613篇
  2019年   2378篇
  2018年   2257篇
  2017年   2467篇
  2016年   2658篇
  2015年   2074篇
  2014年   3401篇
  2013年   15236篇
  2012年   4171篇
  2011年   4079篇
  2010年   3641篇
  2009年   4264篇
  2008年   3833篇
  2007年   3159篇
  2006年   3533篇
  2005年   3529篇
  2004年   3073篇
  2003年   2842篇
  2002年   2823篇
  2001年   2583篇
  2000年   2506篇
  1999年   2399篇
  1998年   2257篇
  1997年   2300篇
  1996年   2157篇
  1995年   1956篇
  1994年   1975篇
  1993年   1946篇
  1992年   1995篇
  1991年   1889篇
  1990年   1786篇
  1989年   1658篇
  1988年   1592篇
  1987年   1596篇
  1986年   1676篇
  1985年   2420篇
  1984年   2293篇
  1983年   2090篇
  1982年   1958篇
  1981年   1890篇
  1980年   1863篇
  1979年   1782篇
  1978年   1614篇
  1977年   1616篇
  1976年   1369篇
  1975年   1269篇
  1974年   1183篇
  1973年   1183篇
  1972年   897篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
831.
832.
833.
834.
835.
This paper investigates whether governments can change market structures through interventions. We study the effects of four political events over the life cycle of the market for daily newspapers in the Netherlands. We find that policy measures meant to lower entry barriers in an expanding industry created new entry and increased survival chances for potential entrants and incumbent newspapers. Exit barrier enhancing policies to reduce concentration tendencies have not been successful.  相似文献   
836.
Lejeune  Miguel A. 《NETNOMICS》2002,4(2):145-162
Denial of Service (DoS) attacks consist of overwhelming a server, a network or a Web site in order to paralyze its normal activity. The additional parameter in Distributed Denial of Service (DdoS) attacks is the distributing strategy. It means that DDoS attacks do not come from a single computer but stem from all accessible channels and servers. Consequences are multiple, ranging from system errors, temporary inability to access the Web site for normal users to challenging the actual reliability of the Internet. Despite this, Internet users show carelessness. The explanation lies in the specificities of DDoS attacks. We explore possibilities to raise users' awareness about the actual amplitude of problems caused by DDoS attacks. We suggest a careful examination of Internet pricing mechanisms and switching from flat to usage-constraining pricing schemes.  相似文献   
837.
The use of transferable discharge permits as a water pollution control policy is rapidly increasing in the United States. Drawing on evidence from existing water quality trading programs, this paper provides a taxonomy of the forms that such markets take. Four main structures are identified: exchanges, bilateral negotiations, clearinghouses, and sole-source offsets. Each of these structures has its own strengths and weaknesses; none is optimal for all scenarios. Since market structure is largely determined by a program's rules, policy makers should be aware of the differences between these structures and the conditions under which each comes to be.  相似文献   
838.
Agricultural policy reform has been an important source of change in the Chinese agricultural sector. The reforms led to productivity growth and helped China to pursue its self-sufficiency goal especially in the grain sector. In order to analyze whether observable productivity growth stems from technologically induced components or from the market induced parts, a multi-input–multi-output model is derived by using an econometric distance function framework. A decomposition allows to distinguish allocative effects, scale effects, technological change, and technical efficiency change. Data on farms in Zhejiang from 1986 to 2000 are used to analyze the impact of policy reform.  相似文献   
839.
Elicitation using multiple price list formats   总被引:2,自引:0,他引:2  
We examine the properties of a popular method for eliciting choices and values from experimental subjects, the multiple price list format. The main advantage of this format is that it is relatively transparent to subjects and provides simple incentives for truthful revelation. The main disadvantages are that it only elicits interval responses, and could be susceptible to framing effects. We consider extensions to address and evaluate these concerns. We conclude that although there are framing effects, they can be controlled for with a design that allows for them. We also find that the elicitation of risk attitudes is sensitive to procedures, subject pools, and the format of the multiple price list table, but that the qualitative findings that participants are generally risk averse is robust. The elicitation of discount rates appear less sensitive to details of the experimental design. Electronic Supplementary Material Supplementary material is available in the online version of this article at . JEL Classification C9, D81, D91 An erratum to this article is available at .  相似文献   
840.
There is ongoing debate about the apparent weak or negative relation between risk (conditional variance) and expected returns in the aggregate stock market. We develop and estimate an empirical model based on the intertemporal capital asset pricing model (ICAPM) that separately identifies the two components of expected returns, namely, the risk component and the component due to the desire to hedge changes in investment opportunities. The estimated coefficient of relative risk aversion is positive, statistically significant, and reasonable in magnitude. However, expected returns are driven primarily by the hedge component. The omission of this component is partly responsible for the existing contradictory results.  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