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   70050篇
  免费   3074篇
  国内免费   13篇
各国政治   4649篇
工人农民   2915篇
世界政治   5903篇
外交国际关系   4107篇
法律   30274篇
中国共产党   383篇
中国政治   2222篇
政治理论   20572篇
综合类   2112篇
  2023年   358篇
  2021年   454篇
  2020年   1246篇
  2019年   1535篇
  2018年   1642篇
  2017年   1952篇
  2016年   2157篇
  2015年   1883篇
  2014年   2195篇
  2013年   10708篇
  2012年   1853篇
  2011年   2137篇
  2010年   2211篇
  2009年   2483篇
  2008年   2136篇
  2007年   2013篇
  2006年   2220篇
  2005年   2040篇
  2004年   1858篇
  2003年   1571篇
  2002年   1598篇
  2001年   1453篇
  2000年   1208篇
  1999年   1097篇
  1998年   1052篇
  1997年   954篇
  1996年   926篇
  1995年   883篇
  1994年   897篇
  1993年   932篇
  1992年   858篇
  1991年   883篇
  1990年   836篇
  1989年   897篇
  1988年   877篇
  1987年   905篇
  1986年   862篇
  1985年   936篇
  1984年   853篇
  1983年   898篇
  1982年   853篇
  1981年   810篇
  1980年   629篇
  1979年   632篇
  1978年   556篇
  1977年   498篇
  1976年   464篇
  1975年   376篇
  1974年   378篇
  1973年   391篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
In the early 1970s, Grand Canyon National Park intended to designate its land to “Wilderness,” including the controversial Colorado River corridor. However, by the end of the 1970s the potential for Wilderness designation was off the table, and would never seriously return for genuine consideration. Using Schattschneider's model of conflict, we explain how the organization of this conflict privileges the “causal story” of Wilderness opponents, and therefore why the canyon is not designated. It is our contention that members of Congress will not stand forward to support Wilderness designations without simultaneously providing benefits for extractive land use because (1) congressional representatives are more penalized for supporting than opposing Wilderness designations, (2) Wilderness advocacy groups do not pressure congressional delegates as firmly as opposition groups, and (3) key local congressional members are not likely to see Wilderness as a salient issue worth the risk of negative exposure. If these findings hold, the implication is that we may have reached the end of significant Wilderness designations in highly visible areas, unless critical aspects in land use conflict change.  相似文献   
22.
Numerous accounts reveal that congressional leaders often secure “hip‐pocket votes” or “if you need me” pledges from rank‐and‐file legislators. These are essentially options on votes. Leaders exercise sufficient options—pay legislators to convert to favorable votes—when those options will yield victory. Otherwise, they release the options. A model shows that this optimal strategy for leaders produces many small victories, few small losses, and losses that are, on average, larger than victories. We find precisely these patterns, hence strong evidence for vote options, in Congressional Quarterly key votes from 1975 through 2001 and in non‐key votes from the 106th Congress (1999–2000).  相似文献   
23.
This concept paper presents a theory of environmental scarcity developed byHomer-Dixon. Homer-Dixon developed a model to describe the consequences of scarcity for sub-national violence in third world countries. This paper hasfour interrelated purposes. First, it presents the model of scarcity developedby Thomas Homer-Dixon in 1999. Second, it assesses the way in which the scarcity model contextualizes criminal justice and criminology research, andby extension, how research in crime and justice processes can broaden the scarcity model. Third, it applies elements of the model to the United States,a goal that represents a generalization of the model from third-world to first-world settings. Fourth, it presents a particular case, the migrationof African-Americans from the rural South to urban centers in the 1950s and1960s and consequent inner-city violence in the 1960s, that displays manyelements of the environmental scarcity model.  相似文献   
24.
In 1991 the FCC implemented a price cap plan for local exchange carriers' interstate access service designed to deal with the regulatory boundaries problem arising from the breakup of AT&T in 1984. The experience with the price cap plan demonstrates the difficulty of predicting productivity growth accurately and makes clear that regulators cannot depend upon a pure price cap plan to keep prices within a reasonable range of costs. With periodic reviews to readjust plan parameters, however, a price cap plan can maintain the rate-of-return close to the target rate-of-return without diminishing the price cap plan's incentives for efficient production. A simple method of recalculating the X-factor based on the rate-of-return over the previous three years worked well in simulations. If this procedure had been used over the price cap period 1991 to 2000, prices would have been 20 percent lower and expenditures on LECs' telecommunications service subject to a price cap would have been $3.8 billion lower.  相似文献   
25.
This paper considers technology transfer from a holistic perspective, defining and integrating all essential elements. Technology, technology ownership, and technology transfer are defined to enable practical management of the value of technology as an organizational asset. Concepts from value-chain movement of technology in commercial product development are used to develop a complete, detailed vision of technology transfer across corporate boundaries. Lessons enable development of a productive technology-transfer function that will speed evolution of technology to product and enable creation of new wealth.  相似文献   
26.
罪刑法定主义应当是形式与实质的统一,以此为基础的犯罪概念和犯罪成立要件也必然具有形式与实质的内容。不同法系的国家实现犯罪成立要件实质化的途径各有千秋。  相似文献   
27.
There is widespread concern that higher education is being compromised by being turned into a ‘commodity’ to be ‘consumed’. This article represents an initial attempt to explore the trends in both the UK and US, and considers how the law has responded to them. It argues, however, that there is an important distinction to be drawn between ‘commodification’ and ‘consumerism’. Education has always been a commodity to be bought and sold; the true danger lies in the move to a ‘rights-based’ culture where students (and politicians) see education merely as something to be ‘consumed’ rather than as an activity in which to participate. Whilst the law seems thus far to have been something of a bulwark against this movement, it remains an open question as to whether this will continue to be the case if HEIs do not themselves act more proactively in challenging this damaging view of higher education.  相似文献   
28.
Weit weg und mittlerweile doch sehr nah liegt die Antarktis, wenn es um Klima- und Umweltschutz geht. Forschung und Tourismus strapazieren den au?ergew?hnlichen Naturraum. Der Beitrag zeigt auf, mit welchen Steuerungsans?tzen Deutschland seinen Verpflichtungen zum Antarktisschutz gerecht werden will. Ausgehend von einigen Informationen über den 6. Kontinent (A.) werden die unterschiedlichen Interessenkonflikte rund um Nutzung und Schutz der Antarktis illustriert (B.). Im Anschluss daran wird der zugeh?rige internationale und nationale Rechtsrahmen kurz vorgestellt (C.), ehe verschiedene Facetten des deutschen Ausführungsgesetzes n?her beleuchtet werden (D.). Flankierend wird neben dem Ordnungsrecht eine gute fachliche Praxis in Form eines Leitfadens als Element nichtrechtlicher Steuerung genutzt (E.). Der Beitrag schlie?t mit Fazit und Ausblick (F.).  相似文献   
29.
新城疫病毒F48E9株M NP F和HN基因的真核表达   总被引:7,自引:4,他引:3  
将新城疫病毒(NDV)F48E9株的M、NP、F和HN基因克隆到真核细胞表达载体 pCAGG上,经酶切、PCR鉴定和序列分析,分别筛选出了含有M、NP、F和HN基因的重组质粒, 命名为pCAGG-M、pCAGG-NP、pCAGG-F和pCAGG-HN。纯化后的重组质粒通过脂质体单独转染HeLa细胞,经间接免疫荧光试验检测到了M、NP、F和HN蛋白的表达。pCAGG-M、 pCAGG-NP、pCAGG-F和pCAGG-HN重组质粒组合共转染HeLa细胞48 h后,可以观察到明显的细胞融合现象。试验结果表明,NDV F48E9株的M、NP、F和HN蛋白均在HeLa细胞内得到了成功表达,同时证明在该表达系统中F蛋白不足以诱导细胞融合。  相似文献   
30.
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