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   9137篇
  免费   244篇
各国政治   462篇
工人农民   271篇
世界政治   669篇
外交国际关系   298篇
法律   5777篇
中国政治   57篇
政治理论   1764篇
综合类   83篇
  2020年   103篇
  2019年   118篇
  2018年   161篇
  2017年   161篇
  2016年   171篇
  2015年   123篇
  2014年   144篇
  2013年   901篇
  2012年   197篇
  2011年   222篇
  2010年   182篇
  2009年   180篇
  2008年   208篇
  2007年   224篇
  2006年   244篇
  2005年   225篇
  2004年   214篇
  2003年   227篇
  2002年   217篇
  2001年   360篇
  2000年   297篇
  1999年   227篇
  1998年   120篇
  1997年   108篇
  1996年   86篇
  1995年   92篇
  1994年   94篇
  1993年   99篇
  1992年   173篇
  1991年   212篇
  1990年   187篇
  1989年   225篇
  1988年   209篇
  1987年   220篇
  1986年   213篇
  1985年   205篇
  1984年   168篇
  1983年   174篇
  1982年   117篇
  1981年   123篇
  1980年   101篇
  1979年   122篇
  1978年   95篇
  1977年   84篇
  1976年   85篇
  1975年   92篇
  1974年   98篇
  1973年   96篇
  1972年   87篇
  1969年   79篇
排序方式: 共有9381条查询结果,搜索用时 15 毫秒
31.
32.
33.
Correlation between plasma and bone marrow tricyclic antidepressants has not been studied before. Two groups of rabbits were given 10 and 20 mg of desipramine/kg body weight, respectively. Desipramine was administered to the animals once daily by mouth for 5 days. On the fifth day the animals were sacrificed and blood and bone marrow samples were collected and analyzed using a high performance liquid chromatographic (HPLC) method. Data showed that a correlation exists between bone marrow and blood desipramine. The bone marrow desipramine concentration increased as its blood levels increased. The average ratio of bone marrow to blood desipramine +/- S.D. (standard deviation) in both dosage groups was 37.2 +/- 4.46 with a range of 30.99-44.82. This investigation is promising and shows that bone marrow could be used as an alternative tissue in the absence of a suitable blood sample.  相似文献   
34.
The Green River Murder Investigation in King County, Washington, is currently the longest active serial murder investigation in U.S. history. During its course, over 26 separate scenes with from one to five victims each have been processed. The experience of the authors is presented in order to acquaint other agencies with techniques of outdoor scene processing that have evolved during recovery of remains from Green River and other skeletal cases.  相似文献   
35.
The population-adjusted rate of teenage suicide in King County, Washington, was reviewed for the 26 years from 1959 to 1984. For the entire period, the rate did not change significantly. An abrupt change did occur during the middle of this period, but, for reasons discussed in the text, this may well represent a change in procedures and philosophy of death certification rather than a real change in rate. Reasons for the apparent discrepancy with national statistics are discussed.  相似文献   
36.
In the statistical interpretation of forensic glass evidence it is standard practice to make the assumption of homogeneity of the refractive index (RI) of the source glass, or of localized homogeneity. However, the work of Locke and Hayes showed that, for toughened windscreen glass, this assumption might not be true. This work is well cited, but there appears to have been little follow-on published research. Furthermore, the toughening process is something known to affect the refractive index, and is a process that float glass does not undergo. Float glass is a major component of casework in New Zealand and for that reason it would be interesting to know whether the findings of Locke and Hayes apply when dealing with float glass. In this paper we describe an experiment similar to that of Locke and Hayes, systematically examining the variation of RI in a pane of float window glass. It was found that, although there were no systematic differences in refractive index, there were observable differences across the pane.  相似文献   
37.
38.
Report of an unusual finding of bones on the shore of the Baltic Sea. Although the morphological findings appeared similar to a human foot skeleton, a quick identification as sea dog bone was possible.  相似文献   
39.
A new solid-phase extraction procedure for the determination of cocaine and benzoylecgonine in amniotic fluid, using high flow co-polymeric sorbents is reported. The recoveries of cocaine and benzoylecgonine within the range 0.1-1 mg/l were 95.7% and 50.3%, respectively. The use of high-flow sorbents allowed the easy extraction of amniotic fluid regardless of sample viscosity or physical nature. The use of these solid-phase columns provided many advantages over the more commonly used solvent extraction, including an increase in extraction speed and efficiency, reduced operator time, reduced solvent use and disposal volumes and exceptional extract quality. Further, the determination of amniotic fluid obtained from pregnant cocaine users may provide important information about handling of cocaine by the fetus at various gestational ages. The procedure was successfully applied to amniotic fluid from suspected cocaine abusers.  相似文献   
40.
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   
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