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   32841篇
  免费   1542篇
  国内免费   5篇
各国政治   1348篇
工人农民   1701篇
世界政治   2166篇
外交国际关系   1116篇
法律   21358篇
中国共产党   8篇
中国政治   234篇
政治理论   6198篇
综合类   259篇
  2021年   159篇
  2020年   570篇
  2019年   627篇
  2018年   1081篇
  2017年   1181篇
  2016年   1165篇
  2015年   727篇
  2014年   771篇
  2013年   3100篇
  2012年   885篇
  2011年   1134篇
  2010年   1114篇
  2009年   1041篇
  2008年   1104篇
  2007年   1118篇
  2006年   937篇
  2005年   842篇
  2004年   840篇
  2003年   798篇
  2002年   755篇
  2001年   1161篇
  2000年   1022篇
  1999年   843篇
  1998年   453篇
  1997年   327篇
  1996年   376篇
  1995年   357篇
  1994年   354篇
  1993年   348篇
  1992年   556篇
  1991年   594篇
  1990年   571篇
  1989年   506篇
  1988年   560篇
  1987年   497篇
  1986年   578篇
  1985年   545篇
  1984年   436篇
  1983年   413篇
  1982年   336篇
  1981年   316篇
  1980年   249篇
  1979年   369篇
  1978年   224篇
  1977年   185篇
  1976年   164篇
  1975年   209篇
  1974年   234篇
  1973年   176篇
  1972年   169篇
排序方式: 共有10000条查询结果,搜索用时 30 毫秒
31.
Lophophora is a member of the Cactaceae family, which contains two species: Lophophora williamsii and L. diffusa. Lophophora williamsii is an illegal plant containing mescaline, a hallucinogenic alkaloid. In this study, a novel method based on a single nucleotide polymorphism (SNP) assay was developed for identifying L. williamsii; this assay reliably detects SNPs within chloroplast DNA (rbcL, matK, and trnL-trnF IGS) and was validated for identifying Lophophora and L. williamsii simultaneously. The chloroplast DNA sequences from four L. williamsii and three L. diffusa plants were obtained and compared using DNA sequence data from approximately 300 other Cactaceae species available in GenBank. From this sequence data, a total of seven SNPs were determined to be suitable for identifying L. williamsii. A multiplex assay was constructed using the ABI PRISM® SNaPshot™ Multiplex Kit (Applied Biosystems, Forster City, CA) to analyze species-specific SNPs. Using this multiplex assay, we clearly distinguished the Lophophora among 19 species in the Cactaceae family. Additionally, L. williamsii was distinguished from L. diffusa. These results suggest that the newly developed assay may help resolve crimes related to illegal distribution and use. This multiplex assay will be useful for the genetic identification of L. williamsii and can complement conventional methods of detecting mescaline.  相似文献   
32.
33.
In the case of suspicious deaths, the technique of 1:1 taping is often used in Belgium. It consists of affixing a large number of adhesive tapes to the body of the victim. It is conventionally aimed at obtaining microtraces (e.g., fibers, hair) and is usually not used for DNA analysis. However, in some cases, DNA analysis of certain areas of interest identified on the 1:1 taping material can offer a last resort solution. The four-step method that is described in this article involves the selection of areas of interest on the body (Step 1), the selection of the corresponding tapes (Step 2), the decontamination of the tapes (Step 3), the selection of areas of interest on the tapes, for DNA sampling (Step 4). The method is illustrated by its successful application in four murder cases. In each case, DNA profiles of good quality could be identified, including profiles of persons different from the victim.  相似文献   
34.
Qualitative interviews with one hundred defendants in Dutch criminal cases examine whether perceived procedural justice is a relevant concern for defendants, and, if so, which procedural justice components they refer to. The study provides a point of epistemological departure from the quantitative studies dominating the field, as it assessed which components of procedural justice (if any) respondents put forward themselves rather than asking about predetermined procedural justice components. The large majority of respondents mentioned procedural justice issues themselves, and six components were at the core of their procedural justice perceptions: (1) information on which decisions are based, (2) interpersonal treatment, (3) due consideration, (4) neutrality, (5) voice, and (6) accuracy. Although these procedural justice components largely correspond with the literature, respondents thus mentioned some components more often, and others less often, than the literature would suggest. In particular, neutrality plays an important role in the Dutch legal context examined here.  相似文献   
35.
Using the 2017 post-election German Longitudinal Election Study (GLES), this article examines the voters for the Alternative for Germany (AfD) in the 2017 German federal election. We show that AfD voters in 2017 were truly ‘flesh of the same flesh’ of the mainstream German political parties, with the AfD drawing its voters from across the political party spectrum as well as from previous non-voters in 2013. In contrast to previous scholarship, we find that in most respects AfD voters in 2017 did not differ demographically from voters for all other parties, be that in terms of gender, education, employment status, and union membership. Furthermore, we find that AfD voters were not driven by anxiety about their own economic situation: they are no ‘losers of globalisation.’ Instead, AfD voters in 2017 were driven solely by two factors: their attitudes towards immigrants/refugees and anti-establishment sentiment/satisfaction with democracy in Germany.  相似文献   
36.
This paper describes several dimensions of the cost of the U.S. response to the threat of terrorism. Following an evaluation of the nature and magnitude of the threat of terrorism against the United States, the paper describes the restrictions on our civil liberties, the fiscal and other costs of the major homeland security measures, the fiscal cost of programs that make no contribution to the defense against terrorism but are rationalized on that ground, and the effects on our language and the potential for civil discourse of an extended defense against terrorism.  相似文献   
37.
38.
In the early 1970s, Grand Canyon National Park intended to designate its land to “Wilderness,” including the controversial Colorado River corridor. However, by the end of the 1970s the potential for Wilderness designation was off the table, and would never seriously return for genuine consideration. Using Schattschneider's model of conflict, we explain how the organization of this conflict privileges the “causal story” of Wilderness opponents, and therefore why the canyon is not designated. It is our contention that members of Congress will not stand forward to support Wilderness designations without simultaneously providing benefits for extractive land use because (1) congressional representatives are more penalized for supporting than opposing Wilderness designations, (2) Wilderness advocacy groups do not pressure congressional delegates as firmly as opposition groups, and (3) key local congressional members are not likely to see Wilderness as a salient issue worth the risk of negative exposure. If these findings hold, the implication is that we may have reached the end of significant Wilderness designations in highly visible areas, unless critical aspects in land use conflict change.  相似文献   
39.
While the concepts of race and ethnicity have been abused historically, they are potentially invaluable in epidemiology and public health. Epidemiology relies upon variables that help differentiate populations by health status, thereby refining public health and health care policy, and offering insights for medical science. Race and ethnicity are powerful tools for doing this. The prerequisite for their responsible use is a society committed to reducing inequalities and inequities in health status. When this condition is met, it is irresponsible not to utilize these concepts.  相似文献   
40.
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