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   3326篇
  免费   35篇
各国政治   32篇
工人农民   32篇
世界政治   615篇
外交国际关系   141篇
法律   2122篇
中国共产党   25篇
中国政治   125篇
政治理论   231篇
综合类   38篇
  2021年   6篇
  2018年   5篇
  2016年   3篇
  2015年   4篇
  2014年   19篇
  2013年   15篇
  2012年   286篇
  2011年   241篇
  2010年   97篇
  2009年   52篇
  2008年   221篇
  2007年   271篇
  2006年   288篇
  2005年   257篇
  2004年   251篇
  2003年   214篇
  2002年   238篇
  2001年   170篇
  2000年   167篇
  1999年   81篇
  1998年   44篇
  1997年   28篇
  1996年   28篇
  1995年   26篇
  1994年   33篇
  1993年   20篇
  1992年   16篇
  1991年   22篇
  1990年   22篇
  1989年   14篇
  1988年   21篇
  1987年   12篇
  1986年   16篇
  1985年   8篇
  1984年   14篇
  1983年   21篇
  1982年   18篇
  1981年   14篇
  1980年   19篇
  1979年   14篇
  1978年   5篇
  1977年   7篇
  1976年   4篇
  1975年   6篇
  1973年   4篇
  1963年   5篇
  1961年   5篇
  1960年   3篇
  1959年   6篇
  1957年   3篇
排序方式: 共有3361条查询结果,搜索用时 15 毫秒
331.
The use of the LightCycler for the detection of Y chromosome SNPs   总被引:3,自引:0,他引:3  
A novel methodology based on PCR monitoring on-line with fluorescent formats using the LightCycler for Y chromosome SNP typing is proposed. The main advantages of the system are the time necessary for the analysis (which is around 20 min), the robustness and the accuracy of the method and especially its sensitivity, which permits the detection of the male component in male-female mixtures up to 1:300 for some of the SNPs.Singleplexes of four different SNPs (M9, sY81, SRY-1532 and SRY-2627) as well as two duplexes (M9 and sY81 on the one hand and SRY-1532 and SRY-2627 on the other) were efficiently implemented. A simultaneous amplification and analysis of the four SNPs is also possible. It seems difficult with the current methodology to implement more than a quadruplex.  相似文献   
332.
This study examines the effects of profound hypothermia on the blood-brain barrier (BBB) permeability in ethanol administrated rats. Vascular permeability to intravenously injected Evans blue (EB) was quantitatively examined in the brain regions of rats. Rats were treated with ethanol acute and chronically. Rectal temperature of rats was dropped into 20+/-1 degrees C during profound hypothermia. Mean arterial blood pressure in both acute and chronic ethanol treatments plus hypothermia significantly dropped into low levels as well as in hypothermia alone (P<0.01). Hypothermia led to a significant increase in the content of EB dye in the brain regions of rats (P<0.05). Both acute and chronic ethanol treatments plus hypothermia did not lead to a significant increase in the BBB permeability against intravenously injected EB dye. We conclude that ethanol intake protects the BBB against the effects of hypothermia.  相似文献   
333.
334.
The 4-methylaminorex (4-MAX) is an amphetamine-related psychostimulant drug that has appeared on the clandestine market with a street name of "U4Euh". This compound exists as four stereoisomers, trans-4R,5R, trans-4S,5S, cis-4R,5S and cis-4S,5R, of which the cis forms have been classified as Schedule I substances in the US. The increasing variety of designer drugs has highlighted the importance of detection, identification, and quantitative measurement of these drugs, including 4-MAX, in biological samples. In the present study, the isomers of 4-MAX were detected in urine of rats treated with the drugs by some but not all of the on-site immunoassays tested, mainly as amphetamine or methamphetamine. To facilitate identification of 4-MAX by laboratories specialized in drug analysis, the electron-ionization mass spectrum and TLC data for underivatized 4-MAX using a routine laboratory drug-screening procedure is provided. In addition, a GC/MS method is described for the quantitative determination of cis- and trans-4-MAX as tert-butyldimethylsilyl-derivatives in plasma, urine and tissue.  相似文献   
335.
336.
337.
338.
339.
一九七○至一九七二年,应东盟国家的要求,联合国经济及社会理事会研究中心在亚洲及太平洋经济社会委员会、贸易及发展会议和粮食及农业组织的参与下,研究了在联盟苑围内扩大经济合作的可能性。研究中心认为,本地区发展经济合作的主要方向应是扩大区域内部贸易和在工业领域进行合作。为此,建议以政府间协定为基础对某些商品实行有选择的贸易自由化、在本地区各国的私营部门采取鼓励建立工业企业的措施,以及按各国之间的协定建立合营的工业项目。 除新加坡以外,东盟其他成员国的制造业处于发展的初级阶段。联盟内部扩大工业合作  相似文献   
340.
Restoration projects and archaeologic excavations in two Canadian prisons resulted in the recovery of the skeletons of six felons executed by judicial hanging. Damage inflicted by hanging on various skeletal elements was observed. Among the injuries seen were fractures of the hyoid cornua, styloid processes, occipital bones, and cervical vertebral bodies (C2) and transverse processes (C1, C2, C3, and C5). Despite the general uniformity of the hanging technique, which involved a subaural knot, the trauma to the skeletal elements and the cause of death varied among individuals. Although some of this variation was probably due to minor differences in hanging practices, individual anatomic peculiarities of the victims likely also contributed.  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