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   2518篇
  免费   113篇
各国政治   166篇
工人农民   90篇
世界政治   217篇
外交国际关系   163篇
法律   1246篇
中国共产党   1篇
中国政治   18篇
政治理论   708篇
综合类   22篇
  2023年   19篇
  2022年   23篇
  2021年   20篇
  2020年   52篇
  2019年   64篇
  2018年   77篇
  2017年   95篇
  2016年   98篇
  2015年   63篇
  2014年   75篇
  2013年   357篇
  2012年   82篇
  2011年   68篇
  2010年   62篇
  2009年   68篇
  2008年   83篇
  2007年   100篇
  2006年   95篇
  2005年   91篇
  2004年   72篇
  2003年   74篇
  2002年   93篇
  2001年   50篇
  2000年   46篇
  1999年   48篇
  1998年   31篇
  1997年   31篇
  1996年   22篇
  1995年   35篇
  1994年   24篇
  1993年   24篇
  1992年   36篇
  1991年   25篇
  1990年   25篇
  1989年   35篇
  1988年   29篇
  1987年   31篇
  1986年   26篇
  1985年   30篇
  1984年   20篇
  1983年   24篇
  1982年   23篇
  1981年   28篇
  1980年   20篇
  1979年   9篇
  1978年   9篇
  1977年   19篇
  1975年   15篇
  1973年   13篇
  1969年   9篇
排序方式: 共有2631条查询结果,搜索用时 15 毫秒
31.
A study of the various stressors faced by interns serving as security assistants at the Tenth Pan American Games and the coping mechanisms they utilized was undertaken during the months of July and August 1987. This study revealed that group development can be altered and maladaptive behavior can result among students experiencing high degrees of stress, frustration, and feelings of helplessness, who are subject to a leadership void. The data strongly support the need for planners of similar large-scale internship programs to consider group processes, organizational factors, and interpersonal relations if organizational goals are to be achieved, maladaptive coping mechanisms are to be avoided, and student stress is to be lessened.  相似文献   
32.
The authors are respectively parttime professor sociology at the University of Texas (San Antonio) as well as lecturer at the medical faculty of the State University Limburg (section psychiatry) and researcher at the Research and Documentation Centre of the Ministry of Justice, Schedeldoekshaven 100, 2511 EX The Hague, The Netherlands. Dorette Courtar, a mobility programme exchange student at the University of Maastricht and the Stockholm University, assisted in the basic research. We would like to thank Paulina Loennroth and the mayor of Hulst, dr. A.A.L.G.M. Kessen, both connected to the ECAD and Paul Vasseur, Urban Weber, Suzanne Schardt, all connected to the ECDP for their information and comments.  相似文献   
33.
This paper describes the analytical methodology for the determination of MDMA, MDA, MDEA and MBDB in oral fluid. After a liquid–liquid extraction, the analysis was carried out by high performance liquid chromatography (HPLC), with fluorescence detection. The detector wavelength was fixed at 285 nm for excitation and 320 nm for emission. The mobile phase, a mixture of phosphate buffer (pH = 5) and acetonitrile (75:25), and the column, Kromasil 100 C8 5 μm 250 mm × 4.6 mm, allowed good separation of the compounds in an isocratic mode in only 10 min. The method was validated and showed good limits of detection (2 ng/mL) and quantitation (10 ng/mL) for all the amphetamine derivatives. No interfering substances were detected. A stability study of these compounds in oral fluid stored at three different temperatures (−18, 4 and 20 °C) over 10 weeks was conducted, showing a time-dependent degradation of the four compounds.  相似文献   
34.
Drug trade is widely seen as a phenomenon rather new to the Netherlands. However, at the beginning of the 20th century the Dutch pharmaceutical industries were already extensively involved in the production of both opiates and cocaine, and they went on exporting large quantities of these drugs after the Opium Act (1919) took force. Until the 1960s, arrests were not at all common, and these largely affected minority groups like Chinese opium smokers and black marijuana users. Since then, drug control efforts have increased by leaps and bounds. At first, cannabis was the main target; then the focus turned to heroin, and that was later joined by cocaine. This paper traces the history of the drug trade and drug control in the Netherlands, with emphasis on their development in Amsterdam. The conclusion is reached that, in spite of drastic changes in both drug trade and drug control, certain ideologies, constructs and strategies have remained remarkably stable.  相似文献   
35.
36.
37.
The Biden administration faces the opportunity to reset U.S. policy towards Africa and possesses a variety of tools to use in doing so, including traditional diplomacy, economic statecraft, development assistance, and military engagement. With the increased militarization of U.S. foreign policy over the past few decades, there is an unfortunate tendency to default to military engagement when confronted with even remote threats to U.S. national security interests, and Africa is no exception. With vital security interests in Africa, it can be argued that military engagement should be limited in its application and targeted to those situations that do not lend themselves to solution through traditional diplomacy or development assistance.  相似文献   
38.
39.
40.
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