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   16807篇
  免费   1328篇
各国政治   624篇
工人农民   594篇
世界政治   1282篇
外交国际关系   485篇
法律   12088篇
中国共产党   1篇
中国政治   131篇
政治理论   2837篇
综合类   93篇
  2020年   392篇
  2019年   428篇
  2018年   502篇
  2017年   546篇
  2016年   561篇
  2015年   483篇
  2014年   526篇
  2013年   1706篇
  2012年   392篇
  2011年   499篇
  2010年   632篇
  2009年   608篇
  2008年   434篇
  2007年   395篇
  2006年   477篇
  2005年   355篇
  2004年   371篇
  2003年   336篇
  2002年   299篇
  2001年   702篇
  2000年   590篇
  1999年   462篇
  1998年   217篇
  1997年   198篇
  1996年   152篇
  1995年   177篇
  1994年   185篇
  1993年   150篇
  1992年   322篇
  1991年   355篇
  1990年   337篇
  1989年   342篇
  1988年   315篇
  1987年   285篇
  1986年   300篇
  1985年   312篇
  1984年   304篇
  1983年   265篇
  1982年   201篇
  1981年   198篇
  1980年   159篇
  1979年   216篇
  1978年   133篇
  1977年   104篇
  1976年   91篇
  1975年   107篇
  1974年   124篇
  1973年   113篇
  1972年   92篇
  1971年   89篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
A simple and sensitive method is described for quantitative analysis of chlorpromazine in blood, serum, urine and tissue homogenate. The chlorpromazine cation radical produced by adding perchloric acid and 2,3-dichloro-5,6-dicyano-p-benzoquinone to the sample can be detected by the ESR method at room temperature. The sensitivity limit is 10 ng, that is, 20 μl of the solution containing 0.5 μg chlorpromazine/ml. The time needed for the measurement is within 10 min. The chlorpromazine radical thus produced is very stable; for example, 95% of the radical was observed after 24 h. The advantage of this method is discussed by comparing with the ordinary spectrophotometry which requires the purification of the sample.  相似文献   
43.
44.
Research has indicated that school factors such as communal school organization and student bonding are predictive of school disorder, with greater communal organization and greater student bonding leading to less delinquency and victimization. Data from a nationally representative sample of 254 public, nonalternative, secondary schools were used to examine structural equation models representing hypothesized relationships among communal school organization, student bonding, and school disorder. The hypothesis that communally organized schools would have less disorder held true for teacher victimization and student delinquency, but not for student victimization. In addition, the hypothesis that the relationship between communal school organization and school disorder would be mediated by student bonding was supported for student delinquency, but not for teacher victimization.  相似文献   
45.
To demonstrate that norms have independent causal power, constructivists de-emphasise material factors related to state interests and highlight social factors. Similarly, they conceptualise international organisations as autonomous from state influence, and focus on cases featuring non-state actors that stimulate a “tipping point” of norm diffusion among states in advance of state sponsorship. By contrast, this article utilises an historical materialist approach that admits both social and material data to examine the contrasting case of population control. It finds that US corporate foundations, eugenist demographers, feminist birth control activists and related NGOs conceptualised and promoted population control in the United States, at the United Nations, and across developing countries. However, the tipping point of norm diffusion occurred only after the United States publicly advocated population control. Indeed, material and social factors were inextricably bound together.  相似文献   
46.
47.
48.
49.
Esophageal and tracheal fistulas, which occur in 0.05% of medicolegal autopsies, were demonstrated in three cases by a postmortem radiographic technique using silicone rubber/lead oxide as a contrasting medium that vulcanizes at room temperature. In one 83-year-old male, a tracheoesophageal fistula was detected, which had developed after surgical repair of an esophageal rupture caused by a flexible fiberoptic endoscope. In a second case, carcinoma of the esophagus in a 78-year-old male had eroded the trachea and arcus of the aorta creating a fatal tracheoesophagoaortic fistula. In a third case, 55-year-old female developed a tracheobrachicephalic artery fistula as a result of an infiltrating cystic adenocarcinoma of the trachea, resulting in a fatal hemorrhage into the trachea. The results of this study indicate that diagnostic radiologic methods using a vulcanized contrasting medium are useful in supplementing normal dissection in autopsy cases with suspected fistulas of the esophagus or trachea.  相似文献   
50.
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