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   12586篇
  免费   346篇
各国政治   486篇
工人农民   464篇
世界政治   931篇
外交国际关系   426篇
法律   8174篇
中国政治   94篇
政治理论   2305篇
综合类   52篇
  2020年   152篇
  2019年   212篇
  2018年   259篇
  2017年   283篇
  2016年   277篇
  2015年   172篇
  2014年   271篇
  2013年   1237篇
  2012年   306篇
  2011年   330篇
  2010年   282篇
  2009年   311篇
  2008年   362篇
  2007年   392篇
  2006年   351篇
  2005年   298篇
  2004年   333篇
  2003年   317篇
  2002年   258篇
  2001年   579篇
  2000年   534篇
  1999年   389篇
  1998年   162篇
  1997年   147篇
  1996年   129篇
  1995年   123篇
  1994年   123篇
  1993年   99篇
  1992年   251篇
  1991年   276篇
  1990年   259篇
  1989年   275篇
  1988年   240篇
  1987年   257篇
  1986年   227篇
  1985年   239篇
  1984年   209篇
  1983年   202篇
  1982年   135篇
  1981年   149篇
  1980年   99篇
  1979年   165篇
  1978年   117篇
  1977年   92篇
  1976年   81篇
  1975年   85篇
  1974年   103篇
  1973年   110篇
  1972年   79篇
  1971年   83篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
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   
103.
Social scientists have theorized about the cycle of domestic violence in family abuse. Little research has addressed dating violence as a consequence to the experience of domestic violence by children. This article deals with the self-reported experience of dating violence by high school students from abusive and nonabusive households. A survey was conducted of 1,353 students in a rural area of North Dakota. Results indicated that students from abusive households showed significantly higher incidence of dating violence than those from homes where no abuse was evident. However, less than one in five of the students from abusive home reported dating violence, providing little support for the cycle of violence hypothesis. Students from abusive homes viewed violence as negatively as students from nonabusive homes. Thus, while there are significant differences between the two groups, there are also important similarities. Although there is apparently a greater risk of dating violence among students who have experienced violence at home, these data do not support the idea of an inescapable pattern of violence among adolescents who have experienced violence themselves.  相似文献   
104.
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   
105.
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   
106.
107.
In the forensic science laboratory, the recovery of spermatozoa from vaginal swabs, or vaginal cells from penile swabs, can help determine if sexual intercourse may have taken place. There are several methods used to recover spermatozoa and cells from the swabs before visualisation on a microscope slide and most of these methods use water. Phosphate buffered saline (PBS) is a non-toxic solution used in many biological laboratories. Unlike water, PBS prevents cells rupturing or shrivelling up due to osmosis. This study demonstrates that PBS can be used for the extraction of spermatozoa and cells from swabs and that PBS does not affect subsequent DNA profiling.  相似文献   
108.
Sixteen major evaluations of programs to prevent school bullying, conducted in 11 different countries, are reviewed in detail. Of these 16 evaluations, 8 produced desirable results, 2 produced mixed results, 4 produced small or negligible effects, and 2 produced undesirable results. These varying findings may reflect variations in programs, in implementation, in assessment methods, or in evaluation designs. It is concluded that high-quality evaluations are needed in the future, with randomized designs, theoretically grounded interventions, multiple measures of bullying, and attempts to disentangle the effectiveness of different program components.  相似文献   
109.
The 2003 Duma election resulted in the victory of the party of power, thereby strengthening managed democracy in Russia. Since then, political trends in Russia's regions and rural politics provide considerable evidence of the increasing ability of pro-Kremlin forces to maximise their electoral fortunes in national contests. These political trends make it likely that United Russia will not only emerge as the dominant party in the 2007 Duma election, but will provide the Kremlin and Putin's successor with a compliant lower house. The outcome is that Putin's successor will find the political infrastructure to continue managed democracy.  相似文献   
110.
Henrard  K. 《荷兰国际法评论》2005,52(1):159-163
Netherlands International Law Review -  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