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   1509篇
  免费   85篇
各国政治   90篇
工人农民   70篇
世界政治   132篇
外交国际关系   116篇
法律   807篇
中国政治   16篇
政治理论   353篇
综合类   10篇
  2023年   24篇
  2022年   19篇
  2021年   23篇
  2020年   39篇
  2019年   60篇
  2018年   63篇
  2017年   68篇
  2016年   79篇
  2015年   45篇
  2014年   68篇
  2013年   224篇
  2012年   67篇
  2011年   51篇
  2010年   43篇
  2009年   45篇
  2008年   53篇
  2007年   69篇
  2006年   53篇
  2005年   68篇
  2004年   50篇
  2003年   46篇
  2002年   61篇
  2001年   28篇
  2000年   25篇
  1999年   27篇
  1998年   16篇
  1997年   10篇
  1996年   8篇
  1995年   15篇
  1994年   13篇
  1993年   5篇
  1992年   21篇
  1991年   8篇
  1990年   7篇
  1989年   11篇
  1988年   9篇
  1987年   7篇
  1986年   10篇
  1985年   9篇
  1984年   4篇
  1983年   8篇
  1982年   4篇
  1981年   3篇
  1980年   4篇
  1975年   3篇
  1973年   2篇
  1972年   2篇
  1971年   2篇
  1969年   3篇
  1966年   3篇
排序方式: 共有1594条查询结果,搜索用时 31 毫秒
91.
Eight Y chromosome short tandem repeat (STR) polymorphisms (DYS19, DYS385, DYS389I, DYS389II, DYS390, DYS391, DYS392, and DYS393) were analyzed in the sample of 117 unrelated Albanian males living in Kosovo. A general STR allelic frequency pattern in the Albanian population from Kosovo corresponds to other European populations. Fourty six haplotypes were observed in single copy. The most frequent haplotypes were (DYS19-DYS385-DYS389I-DYS389II-DYS390-DYS391-DYS392-DYS393) 14-11/11-13-29-24-11-13-13 (10.26%), 14-14/17-12-28-24-10-11-12 (9.40%), 13-16/18-13-30-24-10-11-13 (9.40%), and 14-17/17-13-31-24-10-11-13 (9.40%).  相似文献   
92.
93.
An HPLC-APCI-MS(/MS) method for the (trace) analysis of the most commonly encountered peroxide explosives, hexamethylenetriperoxidediamine (HMTD) and triacetonetriperoxide (TATP), has been developed. With this method, HMTD and TATP have been analyzed in the same run. (Pseudo-)molecular ions of these peroxides have been obtained as base peak under the same condition. A series of product ions was produced from these pseudo-molecular ions ([HMTD - 1]+ and [TATP + NH4]+) in the MS/MS analysis. We also pioneered in showing that a TATP molecular ion [TATP + H]+ can be observed with HPLC-MS/MS. The limit of detection for HMTD and TATP was 0.26 and 3.3 ng, respectively, on column by HPLC-MS in the Full Scan mode and 0.08 and 0.8, respectively, by HPLC-APCI-MS/MS in Selected Reaction Monitoring (single mass unit) mode. The method presented has been applied successfully for the identification of peroxides in the bulk solid state (powder sample), as well as in post-blast extracts originating from a forensic case. For the post-blast extracts, the use of tandem MS has been shown clearly to be of crucial importance for the identification and detection of the peroxide explosives.  相似文献   
94.
95.
Allele frequencies for 16 short tandem repeats (STR) loci were determined with a sample of 230-300 unrelated individuals from the population of Rio de Janeiro, Brazil. The loci are the most commonly used in forensic and paternity testing, being analysed by the Identifiler (Applied Biosystems) and PowerPlex 2.1 (Promega) commercial kits. It was proved that Penta E and D18S51 are the most polymorphic loci.  相似文献   
96.
Nine STRs loci have been typed in a sample from Córdoba (Argentina).  相似文献   
97.
Genotype polymorphism studies at the 13 loci STRs included in the combined DNA index system [CODIS and PCR-based short tandem repeat loci, in: Proceedings of the Second European Symposium on Human Identification, Promega Corporation, Madison, WI, 1998, pp. 73-88; J. Forensic Sci. 46 (2001) 453] (CODIS: D3S1358, HUMvWA31, HUMFGA, D8S1179 D21S11, D18S51, D5S818, D13S317, D7S820, HUMTH01, HUMTPOX, HUMCSF1PO and D16S539) were carried out in a sample of 1429 unrelated Colombian individuals belonging to 25 different departments. As many other countries in Latino-America, Colombia shows an important admixture component, basically integrated by Amerindians, European-descendants and African-descendants. Due to the fact that only partial population analyses have been carried out in the country, the main aim of the present analysis is to establish a database of forensic interest based on the widely used CODIS systems covering the main Colombian regions.  相似文献   
98.
Eight Y-chromosome STRs were investigated in a male population sample from Córdoba region (Argentina). Complete Y-chromosomal STRs haplotypes were obtained in 100 individuals, among which 91 different haplotypes were observed. The most common haplotype was shared by 4% of the sample, while 86 haplotypes were unique. The gene diversity was 0.9875 and the discrimination capacity was 0.8600. The combined polymorphism provides a powerful discrimination tool for routine forensic applications.  相似文献   
99.
In recent years, there has been a surge in patenting by Belgian universities. It appears that this increase can be attributed to growth of biotechnology, where there is a greater propensity to patent, to a desire on the part of universities to enhance commercialization through technology transfer offices (TTOs), and to effective collaboration between universities and government-sponsored research centers. Our qualitative analysis reveals that patent statistics could be a misleading indicator of an individual university's technological productivity, since many inventions are developed at universities, yet applied by other institutions.  相似文献   
100.
da Veiga FA  Saraiva CB 《危机》2003,24(2):56-67
Relatively few studies have addressed age patterns of suicide using specifically designed and systematized approaches. Our main objective was to identify and characterize age patterns of suicide in Europe, both on cross-sectional and longitudinal perspectives, based on data comprising the two last decades of the 20th century. A second objective was to determine whether some analytical methods could be useful as complementary approaches to the traditional examination of age-specific rate curves. We identified and characterized four patterns: upward-sloping, convex, downward-sloping, and uniform. The first three reproduce patterns previously described, though we propose some modifications to the respective classification criteria. Longitudinally, pattern stability was found for most countries, but some notable exceptions were detected. From the computation of multiple-decrement life tables by European country, period, and gender, we derived cumulative distributions of age at death for suicide. The results indicate that this methodology is a useful tool, not only for describing and summarizing information, but, more importantly, for providing a better understanding of intrinsic features and complexities of the patterns. Finally, we discuss practical implications of the study in the context of previous theories linking age patterns of suicide to sociological and economic dimensions, and we raise a few questions and hypotheses to be addressed in future research.  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