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   26996篇
  免费   768篇
  国内免费   8篇
财政金融   5205篇
工业经济   2084篇
计划管理   4514篇
经济学   6077篇
综合类   426篇
运输经济   183篇
旅游经济   374篇
贸易经济   4119篇
农业经济   1255篇
经济概况   3457篇
信息产业经济   2篇
邮电经济   76篇
  2021年   190篇
  2020年   369篇
  2019年   492篇
  2018年   587篇
  2017年   653篇
  2016年   583篇
  2015年   417篇
  2014年   664篇
  2013年   2807篇
  2012年   801篇
  2011年   970篇
  2010年   849篇
  2009年   915篇
  2008年   832篇
  2007年   729篇
  2006年   703篇
  2005年   607篇
  2004年   511篇
  2003年   577篇
  2002年   544篇
  2001年   535篇
  2000年   550篇
  1999年   541篇
  1998年   515篇
  1997年   493篇
  1996年   421篇
  1995年   385篇
  1994年   395篇
  1993年   433篇
  1992年   462篇
  1991年   440篇
  1990年   393篇
  1989年   340篇
  1988年   330篇
  1987年   319篇
  1986年   333篇
  1985年   447篇
  1984年   439篇
  1983年   425篇
  1982年   373篇
  1981年   372篇
  1980年   327篇
  1979年   349篇
  1978年   296篇
  1977年   269篇
  1976年   242篇
  1975年   226篇
  1974年   195篇
  1973年   191篇
  1972年   143篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
This paper presents an approach to assessing the efficacy of public spending on research and development in state programs. At present, there is a need to develop a unified approach to the analysis and evaluation of the efficacy of such spending from the perspective of participants in state programs (federal executive bodies). The proposed approach does not allow evaluating the efficacy of public spending on the development of research areas assigned to the authors.  相似文献   
2.
This study investigates the correlates of a resident's walking behaviors and aims to shed light on mechanisms through which walking may be encouraged. The results of this investigation paint a complex and nuanced picture of the residents’ walking behaviors in South East Queensland, Australia. The results suggest that sociodemographic characteristics separately may contribute greatly to whether or not one engages in walking behaviors. Further, cumulatively these differences might be greater for some groups of residents compared to others. One of the most prominent findings of the study is that the purpose, the characteristics of the origin, and the characteristics of the destination of a trip tended to be similar in the heterogeneity they exhibit over the distribution of time spent walking. For example, pick something up, undertake work, or engage in personal business, move to or from a workplace, shop, or social place are activities that tend to be associated with walking as a main mode of transport and a higher number of walking episodes. However, these trips tended to be short.  相似文献   
3.
4.
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   
5.
Review of Quantitative Finance and Accounting - We examine how changes in dividend policy in 2008 as the financial crisis was unfolding influenced firm risk-adjusted returns in the following years....  相似文献   
6.
President Biden was sworn in on January 20, 2021 after a 4‐year term by President Trump. Certainly, Trump's norm breaking presidency impacted Canada in significant ways and the agricultural sector was no exception. In this issue, we have a set of four short articles discussing the possible implications on Canadian agriculture of transitioning from a Trump to Biden presidency. Issues related to Canada‐U.S. agricultural trade, political norms and uncertainty, U.S. domestic support, participation in trade agreements, and U.S.‐China relations are all considered.  相似文献   
7.
李桐 《价值工程》2021,40(27):145-147
民用建筑群风环境的好与坏直接影响着人们生活环境是否宜居,本文针对陕西省安康某建筑群(包含住宅、办公楼和商用建筑)设计文件进行室外风环境评价与分析,通过CFD软件模拟夏季、冬季及全年最大风荷载下多个典型工况的进行分析,对本项目设计文件进行评价并给出相应的建议,为此类大型民用建筑群室外风环境设计提供相应的理论依据和参考.  相似文献   
8.
We model how firms releasing information on different dates causes the CAPM to fail, requiring an additional factor based on the information structure to price assets. We exemplify this mechanism’s empirical relevance using quarterly earnings announcements, which cluster across months along size and book-to-market. Seventy percent of the alpha reduction from including SMB and HML occurs in the four main earnings announcement months. The information structure factor accounts for all of SMB and HML’s seasonal alpha reduction and one third of their overall alpha reduction. Controlling for size and book-to-market, exposures to SMB and HML vary with firms’ earnings announcement month.  相似文献   
9.
Most development projects encounter a highly uncertain entitlement process that is largely uncontrollable by developers. In this study, entitlement is modeled as a separate stage within a compound real option, where developers begin with minimal control (maximum risk) and each successful stage increases control (decreases risk). We solve the model analytically, provide three‐dimensional numerical comparisons, and empirically test the model's predictions using hand collected rezoning petitions. Our main result refines the classic development option model: developers first invest early (secure entitlements) in order to obtain the option to subsequently delay investment (construct the optimal building at the optimal time).  相似文献   
10.
During patent litigation, pay‐for‐delay (P4D) deals involve a payment from a patent holder of a branded drug to a generic drug manufacturer to delay entry and withdraw the patent challenge. In return for staying out of the market, the generic firm receives a payment, and/or an authorized licensed entry at a later date, but before the patent expiration. We examine why such deals are stable when there are multiple potential entrants. We combine the first‐mover advantage for the first generic with the ability of the branded manufacturer to launch an authorized generic (AG) to show when P4D deals are an equilibrium outcome. We further show that limiting a branded firm's ability to launch an AG before entry by a successful challenger will deter such deals. However, removing exclusivity period for the first generic challenger will not.  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