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   4062篇
  免费   90篇
各国政治   182篇
工人农民   144篇
世界政治   208篇
外交国际关系   133篇
法律   2915篇
中国政治   39篇
政治理论   490篇
综合类   41篇
  2021年   24篇
  2020年   39篇
  2019年   62篇
  2018年   83篇
  2017年   77篇
  2016年   98篇
  2015年   47篇
  2014年   69篇
  2013年   391篇
  2012年   103篇
  2011年   157篇
  2010年   93篇
  2009年   75篇
  2008年   130篇
  2007年   138篇
  2006年   123篇
  2005年   93篇
  2004年   135篇
  2003年   123篇
  2002年   131篇
  2001年   161篇
  2000年   146篇
  1999年   115篇
  1998年   28篇
  1994年   25篇
  1993年   29篇
  1992年   71篇
  1991年   87篇
  1990年   92篇
  1989年   96篇
  1988年   97篇
  1987年   95篇
  1986年   77篇
  1985年   80篇
  1984年   71篇
  1983年   63篇
  1982年   27篇
  1981年   24篇
  1979年   34篇
  1978年   36篇
  1977年   24篇
  1976年   27篇
  1975年   31篇
  1974年   38篇
  1973年   39篇
  1972年   39篇
  1971年   38篇
  1970年   40篇
  1969年   33篇
  1968年   28篇
排序方式: 共有4152条查询结果,搜索用时 15 毫秒
261.
The sequence polymorphisms at the mtDNA hypervariable regions I and II (HVR-I and HVR-II) were analyzed in 87 individuals belonging to three religious groups, Hindu, Muslim and Christians of Karnataka (South India). A total of 122 polymorphic sites were observed in the sequenced regions, with HVR-I exhibiting higher variation than HVR-II. The populations exhibited high sequence and nucleotide diversity, alike other studied caste groups of Karnataka.  相似文献   
262.
263.
Allele frequencies for eight tetranucleotide short tandem repeat (STR) loci-CSF1PO, TPOX, TH01, F13A01, FESFPS, vWA, F13B, LPL-were obtained from a population sample of 105-122 unrelated individuals born in Transylvania and Banat (Romania).  相似文献   
264.
A 30-year-old male died in Thailand after a scuffle. The corpse was embalmed and repatriated to France where an autopsy was performed. As usual in cases of embalmment, fluids such as blood and urine were unavailable and the toxicological analyses was performed on the bile and the liver. An overdose of heroin was determined as the cause of death. A review of the literature indicates that several drugs can be detected in fluids and tissues that contain formaldehyde. This case demonstrates that in embalmed corpses, toxicological assessment is still possible, e.g. after heroin fatalities.  相似文献   
265.
We provide a short overview on some current issues in the fields of forensic genetics and ancient DNA (aDNA) analysis. We discuss about the existence of the possible points of contact between the two disciplines, in terms of open problems and the inherent approach to their solution. We mainly focus on the problem of results authentication, its theoretical and technical aspects.  相似文献   
266.
267.
268.
This paper discusses results of a supercritical fluid extraction-gas chromatography/mass spectrometry (SFE-GC/MS) study of small samples ( 100 microg to 1 mg) of human scalp hair. The method offers a number of benefits including greater sensitivity than liquid extraction methods because the entire extractable mass is transferred to the analytical system, compared with only a few percent from a conventional liquid extraction/injection. The project's goals were to determine if SFE-GC/MS analyses of the surface-extractable components of an individual's hair yield consistent chemical profiles and to investigate if the profiles are sufficiently different to distinguish them from those of other individuals. In addition, the mtDNA sequences from ten of the same individuals used in the SFE-GC/MS study from four family units were determined, and, while the families were distinguishable, the maternal relations yielded identical sequences. In tandem, SFE-GC/MS and mtDNA techniques may provide valuable complementary data from forensic hair samples.  相似文献   
269.
The results of extraction of 1,2- and 1,4-dihydroxybenzene from water solutions by the hydrophobic and hydrophilic organic solvents are described. The influence of an extragent nature and of a water-phase pH medium on an extraction degree is demonstrated. The repetition factor needed to extract a preset quantity of examined compounds is calculated.  相似文献   
270.
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