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   12465篇
  免费   353篇
各国政治   580篇
工人农民   456篇
世界政治   955篇
外交国际关系   449篇
法律   7456篇
中国政治   91篇
政治理论   2734篇
综合类   97篇
  2020年   128篇
  2019年   190篇
  2018年   237篇
  2017年   274篇
  2016年   270篇
  2015年   198篇
  2014年   237篇
  2013年   1294篇
  2012年   252篇
  2011年   325篇
  2010年   254篇
  2009年   332篇
  2008年   327篇
  2007年   328篇
  2006年   320篇
  2005年   289篇
  2004年   312篇
  2003年   295篇
  2002年   286篇
  2001年   459篇
  2000年   409篇
  1999年   326篇
  1998年   201篇
  1997年   163篇
  1996年   165篇
  1995年   168篇
  1994年   169篇
  1993年   175篇
  1992年   259篇
  1991年   275篇
  1990年   272篇
  1989年   274篇
  1988年   251篇
  1987年   249篇
  1986年   282篇
  1985年   280篇
  1984年   246篇
  1983年   229篇
  1982年   160篇
  1981年   143篇
  1980年   130篇
  1979年   160篇
  1978年   88篇
  1977年   118篇
  1976年   102篇
  1975年   74篇
  1974年   92篇
  1973年   89篇
  1972年   80篇
  1971年   71篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
A gas chromatographic (GC) fingerprint method, based on the presence or absence of six congeners, was developed for illicit cocaine samples. The fingerprint utilizes the relative abundances of these congeners towards each other, disregarding cocaine as the main constituent, and can be expressed numerically or graphically in the form of pictograms for rapid visual comparison. The method can be applied directly to a solution of the sample in chloroform, without previous workup procedures. More than 70 unrelated samples were analyzed and a great variation was observed in the parameter composition. On the other hand, a remarkable similarity could be seen between related samples. The GC fingerprint method may be considered an important contribution for sample comparison, as is exemplified by a subdivision of the analyzed samples in different categories, based on the number and types of congeners found.  相似文献   
62.
The polymerase chain reaction (PCR) method of specific gene amplification was used in casework to synthesize millions of copies of the polymorphic second exon of the human leukocyte antigen (HLA)-DQ alpha (or DQA1) locus from a variety of evidence samples. The HLA-DQ alpha allelic variants in the amplified deoxyribonucleic acid (DNA) were determined in a rapid non-radioactive test by hybridization to sequence-specific oligonucleotide probes in both the dot-blot and reverse dot-blot formats. This genetic typing system has been subjected to blind proficiency testing; the performance of this test in the analysis of experimentally mixed samples was also evaluated. As of August 1990, over 250 cases have been tested and more than 2000 individual evidence (bloodstains, semen stains, individual hairs, bone fragments, and tissue sections) and reference samples have been analyzed. The first 198 of these cases are summarized in this paper; in 65% of the cases with conclusive results a suspect was included, and in 35%, all suspects were excluded. Individual cases as well as some of the general issues relating to forensic science analysis and this genetic typing system are discussed. The high rate of exclusion reported here combined with the ability of PCR to type old evidence samples suggests the relevance of this genetic test for postconviction review; two cases in which the convicted suspect was excluded are discussed.  相似文献   
63.
64.
An improved method has been developed for the reliable classification of different C1R genetic variant forms from human serum or plasma. The method combines the use of neuraminidase-digested samples followed by monodimensional isoelectric focusing in the pH range 5 to 8 followed by immunoblotting. The method yields a simple pattern, with one major band in homozygote and two major bands in heterozygote cases.  相似文献   
65.
Fabella  R. V. 《Public Choice》1996,89(3-4):325-337
Public Choice - We consider an economy where the rent value depends indirectly on value-adding investment of agents (thus indirectly endogenous) and the win-probability is a function of rent...  相似文献   
66.
67.
68.
We develop a model of the peace dividend and use it to predict the fiscal consequences of a reduction in the demand for military spending. The model is based on the assumption that the political process responds to political demands and costs in a way that maximizes net political benefits. The predictions of our model on how a peace dividend will be allocated over nonmilitary spending, tax relief, and deficit reduction is tested against the experience of eight major wars in United States history.  相似文献   
69.
A method ist described to determine the CO-content in the tissue of muscles. The prepared tissue is pulverized in a swinging mill at the temperature of liquid nitrogen. Parts of the powder are weighed into headspace vessels. Carbon monoxide ist ejected by a formerly described method and measured gaschromatographically. The Fe-content is determined after an acid disintegration by AAS. Acute intoxications lead to higher CO-contents in heart than in periphere muscles. Chronic exposure to carbon monoxide does not produce these differences.  相似文献   
70.
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