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   14987篇
  免费   468篇
各国政治   769篇
工人农民   598篇
世界政治   1003篇
外交国际关系   491篇
法律   9173篇
中国共产党   3篇
中国政治   91篇
政治理论   3187篇
综合类   140篇
  2020年   181篇
  2019年   233篇
  2018年   338篇
  2017年   337篇
  2016年   342篇
  2015年   245篇
  2014年   254篇
  2013年   1640篇
  2012年   354篇
  2011年   371篇
  2010年   328篇
  2009年   353篇
  2008年   396篇
  2007年   371篇
  2006年   425篇
  2005年   366篇
  2004年   366篇
  2003年   356篇
  2002年   352篇
  2001年   460篇
  2000年   424篇
  1999年   335篇
  1998年   209篇
  1997年   204篇
  1996年   176篇
  1995年   169篇
  1994年   167篇
  1993年   191篇
  1992年   284篇
  1991年   324篇
  1990年   295篇
  1989年   312篇
  1988年   282篇
  1987年   315篇
  1986年   306篇
  1985年   302篇
  1984年   279篇
  1983年   293篇
  1982年   196篇
  1981年   181篇
  1980年   162篇
  1979年   196篇
  1978年   147篇
  1977年   127篇
  1976年   121篇
  1975年   117篇
  1974年   131篇
  1973年   134篇
  1972年   116篇
  1969年   97篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
A number of recent studies have explored the consequences ofinterracial peer effects on the academic and social performanceof minority students. This article contributes to that discussion,focusing, however, on perceptions rather than behaviors. Theanalysis suggests that exposure to white peers is associatedwith declining perceptions of racial justice among black andLatino high school students. While cautioning against causalinterpretations of this finding, the article suggests that theintegrationist aims of Brown v. Board of Education will notbe satisfied without more thoughtful and vigorous desegregationefforts.  相似文献   
92.
Ethanol was determined by gas chromatography in a variety of tissues and body fluids secured at autopsy in 61 cases. The specimens tested included right and left heart blood, femoral blood, pericardial fluid, cerebrospinal fluid, vitreous humor, urine, stomach contents, and brain. Statistical analysis of the cases revealed no significant differences among the various blood sites tested. However, the variations in blood ethanol concentrations among the various sampling sites within each case were as follows: 40 cases showed differences of less than 25%; 16 cases revealed variability between 25% and 50%, 4 cases had differences exceeding 50%. In one case, satisfactory blood analyses could not be accomplished. The larger variances occurred especially in those instances in which stomach alcohol concentration was 0.50% or greater. In one case, the variability amongst the different blood sites exceeded 400% (femoral blood--0.043%, right atrium--0.070%, root of aorta--0.156%); the brain was 0.050%, and the stomach contents was 1.2%. For all 61 cases, variances in blood alcohol content among the different sampling sites in a single cadaver ranged from 1.8 to 428%.  相似文献   
93.
94.
95.
Deoxyribonucleic acid (DNA) typing of ribosomal ribonucleic acid (rRNA) genes was performed with a polymerase chain reaction (PCR) assay for species identification. A variable region of the 28S ribosomal RNA gene was amplified with primers complementary to flanking sequences phylogenetically well conserved. The products of twelve animal DNAs (human, Japanese monkey, dog, cattle, pig, cat, rabbit, mouse, rat, chicken, frog, and fish) were separated by polyacrylamide gel electrophoresis, each revealing a few bands ranging from 150 to 100 base pairs. The band patterns obtained from each DNA sample differed in number and size, which indicates the applicability of the method to species identification. Samples containing either as little as 1 pg of DNA or degraded DNA of 0.2 to 0.5 kb in length were able to give detectable bands. Postmortem human tissue DNAs were tested as an example. They showed a pattern identical to the human control one, which was distinct from those of the other animals examined.  相似文献   
96.
Andrew M. Greeley is a priest, sociologist, novelist, and journalist. His scholarly writings concentrate on religion and ethnicity. His other writings range from critiques of the Catholic church to best-selling novels.  相似文献   
97.
98.
This paper describes a collaborative exercise intended to demonstrate whether uniformity of DNA profile results could be achieved between different European laboratories. It was shown that this goal can be obtained provided that a common protocol is followed (specifically the use of a common electrophoretic buffer as being the most important parameter). Generally, lower molecular weight loci (with lower molecular weight fragments) such as YNH24 perform better than higher molecular weight loci such as MS43a. The results of the exercise are discussed in relation to the objectives of the European DNA profiling group (EDNAP).  相似文献   
99.
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   
100.
Despite its original purpose to protect and rehabilitate wayward children, the juvenile system has grown more punitive and has embraced the use of harsher punishments, including execution, for juvenile offenders. Relatively little is known, however, about public attitudes toward the use of capital punishment for juveniles. This research explored the determinants of death penalty opinion, identified the minimum age at which respondents were willing to allow a juvenile to be put to death and examined the willingness of respondents to support an alternative sentence of life without the possibility of parole (LWOP). The results suggested that, while one-quarter of the sample was willing to execute juveniles who were fifteen and under at the time of the crime, there was less support for the execution of juveniles than of adults. In addition, of those who supported the use of the death penalty for juveniles, almost one-half would support LWOP as an alternative to the death penalty.  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