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   9357篇
  免费   266篇
各国政治   497篇
工人农民   427篇
世界政治   554篇
外交国际关系   292篇
法律   5774篇
中国共产党   3篇
中国政治   63篇
政治理论   1932篇
综合类   81篇
  2020年   111篇
  2019年   157篇
  2018年   217篇
  2017年   235篇
  2016年   227篇
  2015年   154篇
  2014年   161篇
  2013年   1060篇
  2012年   239篇
  2011年   238篇
  2010年   201篇
  2009年   224篇
  2008年   275篇
  2007年   233篇
  2006年   264篇
  2005年   243篇
  2004年   250篇
  2003年   214篇
  2002年   220篇
  2001年   272篇
  2000年   282篇
  1999年   202篇
  1998年   133篇
  1997年   133篇
  1996年   121篇
  1995年   109篇
  1994年   106篇
  1993年   123篇
  1992年   188篇
  1991年   209篇
  1990年   189篇
  1989年   189篇
  1988年   168篇
  1987年   183篇
  1986年   181篇
  1985年   170篇
  1984年   162篇
  1983年   185篇
  1982年   103篇
  1981年   100篇
  1980年   81篇
  1979年   113篇
  1978年   79篇
  1977年   81篇
  1976年   63篇
  1975年   60篇
  1974年   68篇
  1973年   76篇
  1972年   65篇
  1968年   55篇
排序方式: 共有9623条查询结果,搜索用时 15 毫秒
61.
62.
The impact of high temperatures (24 to 39 degrees C) and low to moderately high humidities (20 to 70%) on the applicability of TLC systems for drug identification was studied during a 6 month climatologic cycle in Burkina Faso (West Africa). In general, the Rf values as observed on the plates were found to be substantially affected as compared with values obtained at temperate climates. Some TLC systems were more affected than others and the largest deviations of up to 30 Rf units were at low humidities. Tropical conditions also had a negative effect on the reproducibility of Rf values. However, when an Rf-correction procedure was applied, using reference mixtures of known drugs on each plate, accuracy as well as reproducibility of the resulting Rfc values were drastically improved and data thus corrected were found to be compatible with existing TLC data bases developed under moderate climatological conditions. The impact of high to extremely high humidities (70 to 100%) remains to be investigated.  相似文献   
63.
Veto Players and Civil War Duration   总被引:1,自引:0,他引:1  
Civil wars show a remarkable variation in how long they last. Some end within days; others continue for decades. What explains the extreme intractability of some wars while others are resolved quickly? This article argues that conflicts with multiple actors who must approve a settlement (veto players) are longer because there are fewer acceptable agreements, information asymmetries are more acute, and shifting alliances and incentives to hold out make negotiation more difficult. This veto player approach to explaining variation in civil war duration is tested using a new dataset containing monthly data on all parties to each civil war begun since World War II. The statistical analysis shows a strong correlation between the number of veto players and the duration of civil war.  相似文献   
64.
In this study, a new method was developed for the impurity profiling of illicit MDMA tablets. The extraction efficiency, linearity, repeatability and reproducibility of the method were evaluated. Eighty two MDMA tablets coming from presumed unrelated large seizures in 2004 (n >500 tablets) were analyzed by gas chromatography mass spectrometry (GC-MS) in order to assess the discrimination power of the method. The latter was found to be practical, robust, relatively easy to perform, highly discriminative and yielding good chromatography. In addition, some new impurities were detected and identified. Their chemical structures and mass spectra are reported.  相似文献   
65.
Child custody evaluators with experience in mediation may be tempted to use mediation skills and strategies in their evaluation processes. This article explores the benefits and risks of blending mediation with evaluation, comparing the perspectives of professionals and clients.  相似文献   
66.
67.
California is now in its 11th year of mandatory child custody mediation, with a current yearly case volume statewide estimated at 65,494. This article profiles the variations in programs and mediation styles in 56 of the state's 58 Superior Courts. Two research studies provide the basis for the information on program structures, case activity, procedures, agreement formats, recommendations, facilities, security, and fees.  相似文献   
68.
69.
70.
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