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   25784篇
  免费   1444篇
各国政治   962篇
工人农民   1214篇
世界政治   1673篇
外交国际关系   812篇
法律   17311篇
中国共产党   36篇
中国政治   215篇
政治理论   4786篇
综合类   219篇
  2021年   131篇
  2020年   530篇
  2019年   545篇
  2018年   734篇
  2017年   782篇
  2016年   880篇
  2015年   681篇
  2014年   715篇
  2013年   2526篇
  2012年   676篇
  2011年   734篇
  2010年   696篇
  2009年   779篇
  2008年   787篇
  2007年   798篇
  2006年   809篇
  2005年   682篇
  2004年   686篇
  2003年   568篇
  2002年   611篇
  2001年   927篇
  2000年   846篇
  1999年   668篇
  1998年   371篇
  1997年   277篇
  1996年   315篇
  1995年   289篇
  1994年   281篇
  1993年   288篇
  1992年   463篇
  1991年   492篇
  1990年   463篇
  1989年   434篇
  1988年   482篇
  1987年   431篇
  1986年   503篇
  1985年   470篇
  1984年   373篇
  1983年   359篇
  1982年   263篇
  1981年   259篇
  1980年   234篇
  1979年   306篇
  1978年   196篇
  1977年   160篇
  1976年   133篇
  1975年   150篇
  1974年   180篇
  1973年   151篇
  1972年   118篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Bloodstains were made with 200 microliters blood on each of 11 different common substrates to examine the effect of the stain carrier on the amount and quality of DNA recoverable. High-molecular-weight DNA was extracted from all samples after 2 days. The yield of DNA from each sample varied considerably, not only between the different stain carriers but also within a given category. With a DNA yield of up to 10 micrograms, paper, glass, nylon, wood, smooth leather and wool gave the best results, followed by blue denim and wallpaper (up to 6 micrograms), cotton fabric and carpeting (up to 4 micrograms) and suede (up to 2 micrograms). For several stain carriers the DNA-containing solution was contaminated by chemical substances, which in the case of the blue denim, suede, and carpet samples inhibited the digestion of the DNA with restriction enzymes and prevented DNA typing. The different textures of the stain carriers tested and (as for varying yields on the same carrier) the differing degree of loss of DNA during extraction and the physiological variation in the number of leukocytes in human blood are discussed as possible reasons for the wide range of variation in the amounts of DNA it was possible to extract.  相似文献   
82.
83.
On the basis of the uncertainty management model, we argue here that when people are uncertain about an organization's trustworthiness, they may resolve the question how they should react toward the organization by relying on their perceptions of the organization's procedures. As a consequence, we predicted that the reactions of parents whose child was in a day care center would be strongly influenced by their perceptions of the procedures used by the organization that was responsible for their children's day care when the parents would be uncertain about the organization's trustworthiness. However, when parents would be certain that the organization could be trusted they would be less in need of procedural information, yielding less strong effects of perceived procedure on parents' reactions. The findings of a survey study corroborate this line of reasoning. In the discussion it is argued that these findings suggest that people especially rely on their perceptions of procedures when they are uncertain about important aspects of their lives, such as the trustworthiness of organizations that are responsible for their children's day care.  相似文献   
84.
85.
86.
Correlation between plasma and bone marrow tricyclic antidepressants has not been studied before. Two groups of rabbits were given 10 and 20 mg of desipramine/kg body weight, respectively. Desipramine was administered to the animals once daily by mouth for 5 days. On the fifth day the animals were sacrificed and blood and bone marrow samples were collected and analyzed using a high performance liquid chromatographic (HPLC) method. Data showed that a correlation exists between bone marrow and blood desipramine. The bone marrow desipramine concentration increased as its blood levels increased. The average ratio of bone marrow to blood desipramine +/- S.D. (standard deviation) in both dosage groups was 37.2 +/- 4.46 with a range of 30.99-44.82. This investigation is promising and shows that bone marrow could be used as an alternative tissue in the absence of a suitable blood sample.  相似文献   
87.
88.
The formation of adequate mental health systems within prisons has accelerated as a result of successful class action lawsuits. Our recent national survey questioned all state correctional departments about the existence of standards in each system, compliance with such standards, prevalence of class action lawsuits involving the issue of providing adequate mental health services for inmates, issues related to consent decrees, available mental health resources within the correctional system, and the administrative structure of the mental health system. Our purpose was to identify those factors correlated with certified class action lawsuits involving issues related to mental health services. Twenty-one states were involved in such litigation. Only the presence of psychiatric hospitals operated by the department of corrections correlated with the presence of certified class action lawsuits involving mental health services. Prison systems larger than 15,000 inmates were at higher risk for such litigation. Smaller systems having psychiatric hospitals run by the state mental health agency appeared to be at less risk for such litigation.  相似文献   
89.
This paper explores the capacity of alternative theoretical perspectives to explain the self-reported criminality of black and white young adult females. When criminal involvement is regressed on the theory operation-alizations separately by race, a key difference emerges: For white women, significant effects are clustered in the social-psychological theory groups (bonding, attitudes, and maturation), but for the black women the social-psychological variables have only scattered and inconsistent eflects. Instead, for black women structural indicators emerge as the important predictors of criminal involvement.  相似文献   
90.
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