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   16549篇
  免费   1343篇
各国政治   722篇
工人农民   550篇
世界政治   1285篇
外交国际关系   582篇
法律   11073篇
中国共产党   1篇
中国政治   146篇
政治理论   3422篇
综合类   111篇
  2021年   78篇
  2020年   406篇
  2019年   422篇
  2018年   522篇
  2017年   593篇
  2016年   629篇
  2015年   527篇
  2014年   517篇
  2013年   1916篇
  2012年   416篇
  2011年   480篇
  2010年   642篇
  2009年   623篇
  2008年   427篇
  2007年   403篇
  2006年   503篇
  2005年   381篇
  2004年   356篇
  2003年   357篇
  2002年   335篇
  2001年   538篇
  2000年   450篇
  1999年   384篇
  1998年   243篇
  1997年   207篇
  1996年   157篇
  1995年   213篇
  1994年   213篇
  1993年   193篇
  1992年   294篇
  1991年   300篇
  1990年   276篇
  1989年   292篇
  1988年   266篇
  1987年   252篇
  1986年   269篇
  1985年   303篇
  1984年   276篇
  1983年   239篇
  1982年   195篇
  1981年   190篇
  1980年   165篇
  1979年   190篇
  1978年   132篇
  1977年   116篇
  1976年   91篇
  1975年   95篇
  1974年   103篇
  1973年   89篇
  1972年   73篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
In many countries it is left to the discretion of the court to accept or reject conclusions based on sampling procedures as applied to the total drug exhibit. As an alternative to this subjective approach, a statistical basis is presented using binomial and hypergeometric distributions to determine a lower limit for the proportion of units in a population which contains a drug, at a given confidence level. A method for calculating the total weight of a drug present in a population within a given confidence interval is also presented. In the event of no failures (all units sampled contain a drug), a sample size of six or seven units is generally sufficient to state that a proportion of at least 0.70 of the population contains a drug at a confidence level of at least 90%. When failures do occur in the sample, point estimation is used as the basis for selecting the appropriate sample size.  相似文献   
62.
63.
Editors Note: This commentary touches on an aspect of technology transfer to the Third World that often is neglected: Can the technology recipients afford to use it? Although the authors focus on the economics of shrimp production by subsistence farmers, affordability is one of the major concomitant issues of transfer from developed to developing countries.  相似文献   
64.
HIV infection is now perceived as the end stage of a chronic disease that is spreading most rapidly among blacks and Hispanics. The politics of the HIV epidemic in the 1980s were dominated by four interacting factors: fear and fascination; who had the disease and to whom it seemed to be spreading; the endemic problems of United States social policy; and the impact on policy of advances in scientific knowledge. This paper analyzes the political history of each of these factors and describes the dominant policies of the federal government and the states regarding HIV in the areas of surveillance, prevention, research, and financing. Four uncertainties will have a profound influence on the future politics of the HIV epidemic: how the states and the federal government will address the general problems of paying for the care of people with chronic diseases and providing access to care for the uninsured and the underinsured; the number and distribution of the sexual behaviors that transmit infection with HIV and the effectiveness of policies to persuade people to modify these behaviors; precisely who uses addictive drugs and the effectiveness of measures to change their behavior; and the natural history of the virus.  相似文献   
65.
66.
67.
We develop a model of the peace dividend and use it to predict the fiscal consequences of a reduction in the demand for military spending. The model is based on the assumption that the political process responds to political demands and costs in a way that maximizes net political benefits. The predictions of our model on how a peace dividend will be allocated over nonmilitary spending, tax relief, and deficit reduction is tested against the experience of eight major wars in United States history.  相似文献   
68.
A 22-year-old Korean soldier, who had received blows to the neck and epigastrium from an officer 10 h earlier, suddenly died after massive hematemesis. He had been in relatively good health except for episodes of blood-tinged vomiting approximately 5 and 7 months prior to this event. Postmortem examination revealed angiodysplasia involving the gastroesophageal junction, and the stomach was distended with blood. No abnormal findings were present around the whole viscera, and the duodenum was free of blood. The pathologic significance of upper gastrointestinal angiodysplasia as a potential source of bleeding and a chronologic correlation between the trauma and bleeding are discussed.  相似文献   
69.
70.
The primary aim of this paper is to review the literature on preadolescent friendships in order to examine the relationship between preadolescent friendships and social support in adulthood. Social supports are important to health, both directly and as a stress buffer. Few studies, however, have specifically examined adult social supports from the perspective of their developmental precursors and critical developmental periods. Some data indicate that the preadolescent period may be of particular importance to the development of adult social skills and ties. Observational and empirical studies of preadolescent peer relationships, and in particular best friendships, suggest unique and critical contributions to adult social relatedness. Present research is suggestive but is insufficient to validate preadolescence as a critical period in adult social relatedness. Our review has implications for better understanding the mechanisms by which preadolescent friendships effect adult social support—an important mediator of the effects of stress on health. Further longitudinal study is needed.Received Ph.D. from University of Maryland. Research interests are social supports and psychological responses to trauma and disaster.Received M.D. from Yale University. Research interests are social supports and traumatic stress.  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