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   31784篇
  免费   1388篇
各国政治   1387篇
工人农民   1977篇
世界政治   1762篇
外交国际关系   1115篇
法律   20378篇
中国共产党   2篇
中国政治   146篇
政治理论   6256篇
综合类   149篇
  2021年   121篇
  2020年   492篇
  2019年   530篇
  2018年   1848篇
  2017年   1841篇
  2016年   1738篇
  2015年   657篇
  2014年   689篇
  2013年   2677篇
  2012年   781篇
  2011年   1495篇
  2010年   1599篇
  2009年   1213篇
  2008年   1351篇
  2007年   1340篇
  2006年   712篇
  2005年   641篇
  2004年   745篇
  2003年   679篇
  2002年   582篇
  2001年   904篇
  2000年   789篇
  1999年   654篇
  1998年   338篇
  1997年   271篇
  1996年   283篇
  1995年   278篇
  1994年   266篇
  1993年   244篇
  1992年   410篇
  1991年   435篇
  1990年   426篇
  1989年   410篇
  1988年   431篇
  1987年   405篇
  1986年   455篇
  1985年   434篇
  1984年   366篇
  1983年   349篇
  1982年   247篇
  1981年   240篇
  1980年   206篇
  1979年   331篇
  1978年   199篇
  1977年   173篇
  1976年   135篇
  1975年   173篇
  1974年   203篇
  1973年   159篇
  1972年   132篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
*2004年11月,美国总统乔治.W.布什在阿根廷参加第4届美洲国家首脑会议期间,受到了来自民众的强烈抗议。这是自1958年时任美国副总统的理查德.M.尼克松在委内瑞拉被愤怒的民众投掷石块以来,美国政府高级官员在拉丁美洲受到的最差的待遇了。在委内瑞拉总统乌戈.查韦斯和玻利维亚总统候选人埃沃.莫拉莱斯的鼓舞和煽动下,数万名民众举行集会,谴责美帝国主义和已遭搁浅的美洲自由贸易区计划。布什会受到强烈抗议,事先并非毫无征兆。在他出访前夕进行的民意调查显示,53%的南美洲人和87%的拉美“意见领袖”(Opinion Leaders)对美国总统表示反感,…  相似文献   
103.
104.
We investigated the differences in the levels of carboxyhemoglobin (COHb), cyanide (HCN) and petroleum fuels (gasoline and kerosene) between left and right ventricular bloods from fire victims. COHb was slightly, and HCN and petroleum fuels were markedly higher levels in the left than those in the right. These effects were so called 'first pass phenomena' due to the circulation, diffusion and metabolization before the deaths of fire victims.  相似文献   
105.
106.
Blood previously acidified with aqueous saturated ammonium chloride solution was extracted with ethyl acetate. The dried extract was subjected to acetonitrile–hexane partition. The acetonitrile portion was analysed for the presence of acidic and neutral drugs by HPLC–DAD (200 mm×2.1 mm I.D. microbore ODS-Hypersil column) and GC–FID (25 m narrow-bore×0.25 mm I.D. HP-5 column with 0.33 μm film thickness). The protocol was found to be suitable for both clinical toxicology (including emergency toxicology) and postmortem toxicology. At least 66 drugs of interest were unequivocally identified by RRTs (HPLC) and UV spectra (DAD) match while another 12 were unequivocally identified by double RRTs match (HPLC and GC). Quantitation was facilitated by incorporating calibration blood standards in each assay batch. The five drugs most commonly encountered in clinical blood specimens (1150 cases) were: paracetamol (47.4% of the cases); chlormezanone (6.6%), theophylline (1.74%), naproxen (1.65%) and mefenamic acid (1.56%). The following drugs were detected in toxicologically significant quantities in postmortem blood specimens (245 cases): phenobarbitone (1.22% of the cases), naproxen (0.82%), chlormezanone (0.82%), theophylline (0.82%), carbamazepine (0.41%) and paracetamol (0.41%).  相似文献   
107.
108.
Attributions of blame for the first and latest episodes of violence were assessed in a sample of 139 couples who were referred to a mandatory domestic violence treatment program in the military. Use of a methodology which allows for reports of nonmutually exclusive categories of attribution from both members of the dyad revealed more complex patterns of attributions than reflected in the existing literature. In addition, there were low rates of agreement within couples as to who was to blame for the violence. Although both men and women exhibited a high frequency of blaming their partner for both episodes of violence, men were significantly more likely to blame themselves for the latest than for the first episode. Attributions of blame were related to contextual variables in both men and women. Sex specific relationships emerged. These results were discussed with specific reference to predictions derived from attribution theory and their clinical implications.  相似文献   
109.
A minisatellite probe, MZ 1.3, detecting hypervariable fragment patterns was isolated from a human genomic library. A repetitive sequence of 27 bp length was identified which is contained in the probe approx. 40 times. The MZ 1.3 repeat shows variable homology of 53-73% to the repetitive sequence of the protein III gene of the bacteriophage M13 genome. Polymorphic restriction fragment patterns were found with MZ 1.3 using the enzymes Hinf I, BstN I, Hae III, Mbo I, PstI/Pvu II, and Rsa I. An average of 18 polymorphic fragments was observed using Hinf I as enzyme. The band sharing frequency after Hinf I digestion among unrelated individuals was determined to be 23.8 +/- 7.2%. An example for the application of MZ 1.3 to paternity testing in an incest case is given. The probe can be used with radioactive or non-radioactive detection systems. An approach is presented to compare polymorphic fragment patterns from individuals obtained by independent gel runs on the basis of relative band positions (RBP) and calculated in a computerized analysis.  相似文献   
110.
Good gas chromatography (GC) separation of molecules is essential for clean gas chromatography/mass spectrometry (GC/MS) confirmation of compounds. The trifluoro derivatives of ephedrine (E) and methamphetamine (MA) coelute on dimethyl silicone capillary columns, such as DB-1, which are most commonly used by chromatographers. Methods are described to separate E and MA to aid GC/MS confirmations of methamphetamine, ephedrine, or both E and MA together, whichever may be present in Enzyme Immunoassay (EIA)-analyzed amphetamine-positive urine samples. The use of the heptafluoro derivatives of E and MA on a DB-1 column, or the trifluoro derivatives of E and MA on a DB-17 column, is suggested for good gas chromatographic separation.  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