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   20079篇
  免费   500篇
各国政治   788篇
工人农民   745篇
世界政治   1547篇
外交国际关系   667篇
法律   12569篇
中国共产党   2篇
中国政治   90篇
政治理论   3964篇
综合类   207篇
  2020年   240篇
  2019年   280篇
  2018年   367篇
  2017年   424篇
  2016年   471篇
  2015年   317篇
  2014年   373篇
  2013年   1868篇
  2012年   479篇
  2011年   549篇
  2010年   414篇
  2009年   425篇
  2008年   538篇
  2007年   564篇
  2006年   533篇
  2005年   467篇
  2004年   503篇
  2003年   520篇
  2002年   474篇
  2001年   800篇
  2000年   723篇
  1999年   601篇
  1998年   301篇
  1997年   252篇
  1996年   218篇
  1995年   219篇
  1994年   259篇
  1993年   242篇
  1992年   389篇
  1991年   440篇
  1990年   401篇
  1989年   423篇
  1988年   401篇
  1987年   413篇
  1986年   402篇
  1985年   399篇
  1984年   339篇
  1983年   368篇
  1982年   273篇
  1981年   254篇
  1980年   189篇
  1979年   275篇
  1978年   193篇
  1977年   162篇
  1976年   154篇
  1975年   147篇
  1974年   171篇
  1973年   152篇
  1972年   144篇
  1971年   129篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
921.
922.
The article presents the results of an examination of the dry residue of liquor crystallograms (DRLC) using infrared spectroscopy technique. 36 spectrograms were studied. Elements of similarity and difference were revealed in the spectrograms of organic substance (antifreeze, sodium cyclamate and fatty tissue), of DRLC of the crystal-forming matter CuCl(2)x2H(2)0, of DRLC of a live person and cadaveric liquor (with no brain injury in respective case histories), of DRLC of liquor of live persons with a brain injury, of DRLC of liquor of persons who died of a brain injury and of persons who died of other causes.  相似文献   
923.
The paper describes specific morphological features of hairs from the head, beard, chest, axilla, pubis of the native population of Syria, India, Lebanon, Jordan, Yemen, Nepal, Palestine, Bahrain, Iraq and some residents of the Eastern Europe (Russians, Belorussians, Ukrainians). The hairs were studied macroscopically and microscopically (light microscopy). Digital data on hair thickness and number of lines of cuticula pattern were analysed using methods of variance statistics. Original information on some macro- and microscopic characteristics of hair has been obtained for citizens of the above countries.  相似文献   
924.
925.
926.
927.
928.
Bile is, in certain cases, collected together with blood from different sites (heart, brain, femoral), urine and other organs or matrices. This study reports comparative results obtained from the analysis of blood and bile for different drugs found: acetaminophen, amphetamine and related compounds, several antidepressants, several benzodiazepines, cocaine and its metabolites, dextropropoxyphene and its metabolite, hydroxyzine, methadone and metabolite, morphine and codeine, levomepromazine, thioridazine, propranolol, tramadol and its metabolite. Several findings are presented: (1) There were no significant differences in the levels of the compounds among the samples of blood obtained from different sites. (2) Levels in bile are generally several fold higher than those in blood. The mean bile to blood ratios vary from about 1 (for acetaminophen, amphetamine) to about 2000 (for desmethylclobazam). (3) In certain cases (16 over 44), although the drug or its metabolite was not detected in blood from different sites, it was detected in bile. As other authors had advocated, it is very useful to ask the pathologist to take the gall bladder with its contents together with the other samples, in order that the sample of bile can be used in the comprehensive toxicological analysis and therefore be complementary to the other fluids or matrices. An additional advantage for using bile is that the concentrations of drugs or their metabolites are generally several fold higher than their blood concentrations.  相似文献   
929.
In a double-blind placebo controlled study on psychomotor skills important for car driving (Study 1), a 75 mg dose of +/- 3,4-methylenedioxymethamphetamine (MDMA) was administered orally to 12 healthy volunteers who were known to be recreational MDMA-users. Toxicokinetic data were gathered by analysis of blood, urine, oral fluid and sweat wipes collected during the first 5h after administration. Resultant plasma concentrations varied from 21 to 295 ng/ml, with an average peak concentration of 178 ng/ml observed between 2 and 4h after administration. MDA concentrations never exceeded 20 ng/ml. Corresponding MDMA concentrations in oral fluid, as measured with a specific LC-MS/MS method (which required only 50 microl of oral fluid), generally exceeded those in plasma and peaked at an average concentration of 1215 ng/ml. A substantial intra- and inter-subject variability was observed with this matrix, and values ranged from 50 to 6982 ng/ml MDMA. Somewhat surprisingly, even 4-5h after ingestion, the MDMA levels in sweat only averaged 25 ng/wipe. In addition to this controlled study, data were collected from 19 MDMA-users who participated in a driving simulator study (Study 2), comparing sober non-drug conditions with MDMA-only and multiple drug use conditions. In this particular study, urine samples were used for general drug screening and oral fluid was collected as an alternative to blood sampling. Analysis of oral fluid samples by LC-MS/MS revealed an average MDMA/MDEA concentration of 1121 ng/ml in the MDMA-only condition, with large inter-subject variability. This was also the case in the multiple drug condition, where generally, significantly higher concentrations of MDMA, MDEA and/or amphetamine were detected in the oral fluid samples. Urine screening revealed the presence of combinations such as MDMA, MDEA, amph, cannabis, cocaine, LSD and psilocine in the multiple-drug condition.  相似文献   
930.
Allele frequencies for the three STR loci included in the GenePrint CTT multiplex system (HUMTH01, HUMTPOX, HUMCSF1PO) have been determined for the four major sub-populations of New Zealand.  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