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   17586篇
  免费   500篇
各国政治   726篇
工人农民   678篇
世界政治   1470篇
外交国际关系   607篇
法律   10525篇
中国共产党   2篇
中国政治   79篇
政治理论   3820篇
综合类   179篇
  2020年   216篇
  2019年   261篇
  2018年   337篇
  2017年   404篇
  2016年   429篇
  2015年   297篇
  2014年   353篇
  2013年   1712篇
  2012年   416篇
  2011年   440篇
  2010年   361篇
  2009年   394篇
  2008年   453篇
  2007年   481篇
  2006年   456篇
  2005年   411篇
  2004年   415篇
  2003年   429篇
  2002年   386篇
  2001年   690篇
  2000年   627篇
  1999年   520篇
  1998年   300篇
  1997年   248篇
  1996年   210篇
  1995年   209篇
  1994年   250篇
  1993年   227篇
  1992年   349篇
  1991年   376篇
  1990年   336篇
  1989年   346篇
  1988年   325篇
  1987年   338篇
  1986年   343篇
  1985年   338篇
  1984年   296篇
  1983年   325篇
  1982年   264篇
  1981年   242篇
  1980年   182篇
  1979年   250篇
  1978年   168篇
  1977年   144篇
  1976年   137篇
  1975年   124篇
  1974年   137篇
  1973年   127篇
  1972年   116篇
  1971年   96篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
121.
122.
The authors examine the characteristics of threatening and otherwise inappropriate communications sent to members of the U.S. Congress by a sample of 86 subjects, 20 of whom threatened assassination. We quote excerpts from these letters and provide quantitative data on such variables as the volume, duration, form, and appearance of such communications; the enclosures; the subjects' perceived relationships to the recipients; the thematic content of the communications; and the messages and threats communicated. Comparisons between 43 subjects who pursued encounters with members of Congress and 43 who did not revealed 17 factors associated with such pursuit. In this population, threateners were significantly less likely to pursue an encounter than inappropriate letter writers who did not threaten, regardless of the type of threat or the harm threatened. Inappropriate letters to members of Congress are compared with those directed to Hollywood celebrities. Mentally disordered persons writing to public figures often mention and sometimes threaten public figures other than those to whom the letters are addressed, which raises important issues regarding notification of endangered third parties and the sharing of information among protective agencies.  相似文献   
123.
With the rapid growth of cross-border competition among currencies, informed observers predict that the new monetary unions are virtually inevitable in many parts of the world. In fact, predictions of such alliances are misleading and almost certainly wrong. Monetary unions necessarily imply a measure of collective action in the issue and management of money. An alliance requires allies—other states with similar preferences and a disposition to act cooperatively. A survey of proposed monetary unions shows that willing partners among sovereign states are just not all that plentiful. Conceivably some governments could be attracted to less demanding forms of monetary alliance, depending on bargaining context. But prospects for many full new monetary unions are dim at best.  相似文献   
124.
Bioaerosol data is often used in cases of building mold infestation alleging damage or adverse health effects upon occupants, despite the lack of consistent sampling and analytical protocols and numerical health-based standards. The most fundamental problem in these scenarios is defining a “significant” difference between a suspect indoor environment and the reference environment, regardless of the type of sampling and analysis utilized. Data interpretation focused upon differences in absolute numerical concentrations of fungi is subject to wide differences in expert opinion. On the other hand, an objective quantification of differences can be expressed in terms of probability and better meets criteria established in evidentiary rules.  相似文献   
125.
    
Ohne Zusammenfassung  相似文献   
126.
127.
128.
A 6-month-old girl died suddenly without any previous symptoms of heart failure. Autopsy examination showed cardiomegaly (97 g) with a severely fibrotized myocardium. The left coronary artery was originating from the pulmonary artery. Histologically, the myocardium showed myocardial infarcts of different ages, as well as grossly thickened arterial branches due to increased flow in left-right shunt. We suggest that rare anomalies of the coronary arteries should be considered in the autopsies of suspected sudden infant death syndrome cases.  相似文献   
129.
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   
130.
Washington University v. Catalona revolves around ownership of tissue samples provided by patients for research purposes, raising significant ethical and legal questions concerning patient rights, current human research practices, and the treatment of samples as capital resources by the research institution.  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