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   31460篇
  免费   1544篇
各国政治   1322篇
工人农民   1334篇
世界政治   2387篇
外交国际关系   1062篇
法律   20166篇
中国共产党   3篇
中国政治   167篇
政治理论   6311篇
综合类   252篇
  2021年   157篇
  2020年   581篇
  2019年   636篇
  2018年   825篇
  2017年   877篇
  2016年   983篇
  2015年   705篇
  2014年   802篇
  2013年   3251篇
  2012年   807篇
  2011年   846篇
  2010年   801篇
  2009年   850篇
  2008年   859篇
  2007年   877篇
  2006年   872篇
  2005年   758篇
  2004年   777篇
  2003年   699篇
  2002年   718篇
  2001年   1175篇
  2000年   1085篇
  1999年   875篇
  1998年   485篇
  1997年   384篇
  1996年   366篇
  1995年   372篇
  1994年   396篇
  1993年   368篇
  1992年   564篇
  1991年   601篇
  1990年   571篇
  1989年   561篇
  1988年   554篇
  1987年   548篇
  1986年   584篇
  1985年   582篇
  1984年   494篇
  1983年   474篇
  1982年   395篇
  1981年   366篇
  1980年   302篇
  1979年   425篇
  1978年   259篇
  1977年   219篇
  1976年   193篇
  1975年   205篇
  1974年   239篇
  1973年   183篇
  1972年   182篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
201.
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   
202.
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   
203.
204.
205.
Toxicologic findings in the USS Iowa disaster.   总被引:5,自引:0,他引:5  
The toxicologic results from the 47 victims of the explosion on the USS Iowa are presented. Good correlation between carboxyhemoglobin saturations and cause of death was found. There were no correlations between blood cyanide concentrations and causes of death. Volatile analysis suggested postmortem ethanol production rather than antemortem ethanol ingestion. No drugs except nicotine were detected in any of the victims.  相似文献   
206.
207.
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   
208.
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   
209.
210.
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