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   17811篇
  免费   617篇
  国内免费   5篇
各国政治   766篇
工人农民   796篇
世界政治   1239篇
外交国际关系   638篇
法律   11239篇
中国共产党   6篇
中国政治   160篇
政治理论   3401篇
综合类   188篇
  2020年   241篇
  2019年   322篇
  2018年   386篇
  2017年   456篇
  2016年   463篇
  2015年   334篇
  2014年   368篇
  2013年   1718篇
  2012年   497篇
  2011年   525篇
  2010年   426篇
  2009年   467篇
  2008年   546篇
  2007年   585篇
  2006年   541篇
  2005年   501篇
  2004年   505篇
  2003年   524篇
  2002年   455篇
  2001年   708篇
  2000年   588篇
  1999年   504篇
  1998年   262篇
  1997年   185篇
  1996年   211篇
  1995年   182篇
  1994年   215篇
  1993年   209篇
  1992年   338篇
  1991年   372篇
  1990年   363篇
  1989年   295篇
  1988年   339篇
  1987年   284篇
  1986年   328篇
  1985年   297篇
  1984年   240篇
  1983年   232篇
  1982年   186篇
  1981年   195篇
  1980年   133篇
  1979年   183篇
  1978年   128篇
  1977年   109篇
  1976年   103篇
  1975年   128篇
  1974年   137篇
  1973年   111篇
  1972年   105篇
  1969年   100篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
251.
The authors developed a method of malathion insecticide determination in the cadaveric material (blood and wall of the stomach) including extraction of 5 ml of blood (5 g of fragmented tissue of stomach wall) by hexan; preparative chromatographic purification of extract on silicagel layer L 5/40 mkm in hexan-diethyl ether system 10:2; Gas-liquid chromatographic investigation on column with 5% SE-30 and 5% XE-60 (Chromatograph "Colour-106" with thermionic detector). This method makes it possible to detect 72-76% of malathion added.  相似文献   
252.
253.
254.
This paper examines the process by which R&D results funded by the Office of Conservation and Renewable Energy (CE) of the US Department of Energy (DOE) have generated commercial applications. It looks at examples of technology-transfer procedures and activitees across three of CE's component offices that correspond to the major energy end-use sectors: transportation, buildings, and industry. On the surface, the conservation programs would appear to have little strategic consistency and, therefore, lack the clear leadership many seek in a technology-transfer program. However, as an alternative to strategic consistency, one may tailor the technology-transfer approach of each program to its unique circumstances. This paper presents case studies of such tailoring, in which the diversity of approaches mirrors the complexity of the energy end-use markets and the private-public interests that must be negotiated to successfully commercialize energy-saving innovations. The paper discusses the lessons learned about the conditions requiring adaptive design and the structures and practices that have been proven effective.  相似文献   
255.
256.
257.
258.
When technology is transferred from one context to another, it is an established principle that innovation must take place. Even though a technology is well situated in one context, it must be adoptively redesigned for another. The sharper the difference in contexts, the greater the adaptation. This paper describes a program to transfer technology among a very diverse group of organizations: contractors to the US Department of Defense (DOD). Specifically, it describes how the technology of electronic communication, including electronic- data interchange (EDI), is being pursued by both the DOD and its supporters.  相似文献   
259.
This paper describes some of the spinoff benefits that can result from R&D projects, and categorizes them in terms of the dimensions of market and technical newness. These dimensions are discussed with reference to two types of spinoffs: 1) alternative market applications, when the results of an R&D project are subsequently applied to a market or use that differs from the originally intended application, and 2) second-generation technologies, when the technology that was the subject of an R&D project is significantly altered or enhanced in unanticipated ways through subsequent R&D. Examples from the Department of Energy's Energy-Related Inventions Program are integrated into the results of literature review to illustrate key concepts, including core technologies, degrees of market and technology newness, technology robustness, and the nature of connections linking spinoffs to prior R&D investments. The paper concludes by discussing spinoffs as a managerial strategy.  相似文献   
260.
The “tragedy of the commons” is the familiar problem that open access to a common property resource leads to overexploitation and to zero profits. A commons model is applied to an example of state sponsored private violence, the practice of privateering or licensed piracy. It is predicted that the presence of uncertainty about the value of the prey will reduce the amount of exploitation effort, and that industry profits may be positive due to both uncertainty and heterogeneous exploiters. Using data from England's wars with France and Spain between 1625 and 1630, the model suggests that the commons, represented by enemy merchant shipping, was not overexploited and that privateering profits were positive. The dynamic paths of privateering effort, ships seized, and individual firm profits were, however, consistent with the normal expectation that commons exploitation will peak and fall, as competition drives down returns through entry. “England was never richer than when at war with Spain.” Sir Edward Coke   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