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   11291篇
  免费   619篇
各国政治   476篇
工人农民   374篇
世界政治   885篇
外交国际关系   379篇
法律   7440篇
中国共产党   1篇
中国政治   60篇
政治理论   2245篇
综合类   50篇
  2021年   63篇
  2020年   205篇
  2019年   247篇
  2018年   250篇
  2017年   320篇
  2016年   317篇
  2015年   257篇
  2014年   283篇
  2013年   1132篇
  2012年   249篇
  2011年   324篇
  2010年   309篇
  2009年   327篇
  2008年   311篇
  2007年   284篇
  2006年   304篇
  2005年   279篇
  2004年   275篇
  2003年   258篇
  2002年   261篇
  2001年   483篇
  2000年   432篇
  1999年   310篇
  1998年   203篇
  1997年   159篇
  1996年   138篇
  1995年   128篇
  1994年   159篇
  1993年   143篇
  1992年   219篇
  1991年   231篇
  1990年   212篇
  1989年   220篇
  1988年   220篇
  1987年   203篇
  1986年   253篇
  1985年   220篇
  1984年   167篇
  1983年   176篇
  1982年   125篇
  1981年   126篇
  1980年   91篇
  1979年   142篇
  1978年   80篇
  1977年   82篇
  1976年   73篇
  1974年   78篇
  1973年   69篇
  1972年   66篇
  1970年   47篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
No consensus yet exists on how to handle incidental findings (IFs) in human subjects research. Yet empirical studies document IFs in a wide range of research studies, where IFs are findings beyond the aims of the study that are of potential health or reproductive importance to the individual research participant. This paper reports recommendations of a two-year project group funded by NIH to study how to manage IFs in genetic and genomic research, as well as imaging research. We conclude that researchers have an obligation to address the possibility of discovering IFs in their protocol and communications with the IRB, and in their consent forms and communications with research participants. Researchers should establish a pathway for handling IFs and communicate that to the IRB and research participants. We recommend a pathway and categorize IFs into those that must be disclosed to research participants, those that may be disclosed, and those that should not be disclosed.  相似文献   
992.
Typing of X-chromosomal short tandem repeat (STR) loci in a deficiency paternity case revealed a single Mendelian incompatibility between a female child and her putative grandmother, consisting of an opposite homozygosity at locus DXS8378. The presence of a null allele due to a primer binding site mutation on the child's paternally inherited X chromosome was confirmed by amplification with newly designed DXS8378 external primers. Sequencing analysis showed a point mutation (C > T transition at position 168, according to GenBank accession G08098) in the binding site of the original DXS8378 reverse primer.  相似文献   
993.
This study evaluated the use of different degree day (DD) models, developmental thresholds and developmental data sources for estimating postmortem interval (PMI) based on developmental rates of blow flies (Diptera: Calliphoridae). Blow fly evidence was collected from three mock crime scenes and sent for blind analysis of PMI. PMI estimates were calculated using averaging, single sine, double sine, single triangle, and double triangle models of DD calculation with minimum developmental thresholds of 0, 6 and 10 °C and Anderson's, Byrd and Allen's, Greenberg's, Nishida's and Kamal's developmental data sets. These estimates were compared with the actual PMI to determine which combination of DD model, developmental threshold and developmental data provided the most accurate estimate. For all three cases, at least one method gave a PMI estimation that was within 1 day of the actual date of death. There was no variability between PMI estimated using the five models of DD calculation. Overall, as lower developmental threshold increased, the PMI interval estimates increased. Depending on the developmental data set used, increasing the lower developmental threshold caused some overestimations of the date of oviposition, with estimates given that were prior to the actual death. Future PMI estimates should include error ranges, so that overestimation of PMI is avoided.  相似文献   
994.
Short Tandem Repeat polymorphisms have been widely studied in the world, since specific databases are required to produce correct estimates of forensic statistical parameters. In this regard, Y-chromosome STRs have been studied mainly in Europe but are relatively scarce for sub-Saharan populations, despite these populations are represented in most of the Western countries. The aim of this work is to detect groups of populations with the lowest genetic variability within the African context. This allows to establish the relative homogeneity of Y-STRs databases for forensic casework and eventually to provide a wider insight into the African genetic history.  相似文献   
995.
This study extends the current use of Bayesian networks by incorporating the effects of allelic dependencies in paternity calculations. The use of object-oriented networks greatly simplify the process of building and interpreting forensic identification models, allowing researchers to solve new, more complex problems. We explore two paternity examples: the most common scenario where DNA evidence is available from the alleged father, the mother and the child; a more complex case where DNA is not available from the alleged father, but is available from the alleged father’s brother. Object-oriented networks are built, using HUGIN, for each example which incorporate the effects of allelic dependence caused by evolutionary relatedness.  相似文献   
996.
997.
998.
Although the study of local cultures has become established in American sociology, it often ignores the contested nature of how culture emerges and is negotiated within the context of small groups. To this end, we address the concept of infighting, a subtype of conflict, as it operates within a small group framework. Building on an ethnographic study of the Chicago Dyke March, we demonstrate that infighting highlights competing ideologies that may remain implicit in the absence of such conflict. Infighting treats divergent meaning systems as part of local contention between rival cliques and power centers. These ideological battles both reflect pre-existing differences between subgroups and serve to make explicit and public such differences, both in their background characteristics and in their interests. In the process infighting directs attention away from shared concerns and group building to questions of strategy, transforming the small group into an arena of ideological production and factional rivalry. Infighting recasts a group from a space of consensus to a contested political arena. We elaborate four analytic processes through which infighting connects to ideology and small group culture: infighting emphasizes the multivocality of meaning, cultural heterogeneity, an equilibrium of inclusion and group boundaries, and planning in light of ideologies of power.  相似文献   
999.
European Journal of Political Research -  相似文献   
1000.
A simple method was devised to assess dental attrition in terms of its area and number of sites by using dental plaster casts and a computer assisted image analyser. The changes presented on the occlusal surfaces of teeth were investigated for age estimation using these criteria. The area of attrition on each tooth demonstrated a significant positive correlation with age, but a wide individual variation was observed in the values for each tooth. Therefore, this method was unsuitable for accurate age estimation of a single tooth. A strong negative correlation with age was observed in the number of sites of attrition. A multiple stepwise regression analysis using the variables 'attrition area' and 'attrition number' revealed multiple correlation coefficient values of 0.93. The quantitative assessment of both horizontal and vertical factors of dental attrition would be essential to improve the accuracy of this method.  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