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   10745篇
  免费   592篇
各国政治   439篇
工人农民   404篇
世界政治   832篇
外交国际关系   313篇
法律   7198篇
中国共产党   1篇
中国政治   62篇
政治理论   2047篇
综合类   41篇
  2021年   63篇
  2020年   197篇
  2019年   238篇
  2018年   241篇
  2017年   307篇
  2016年   309篇
  2015年   257篇
  2014年   278篇
  2013年   1028篇
  2012年   242篇
  2011年   313篇
  2010年   294篇
  2009年   307篇
  2008年   293篇
  2007年   274篇
  2006年   287篇
  2005年   255篇
  2004年   253篇
  2003年   242篇
  2002年   251篇
  2001年   469篇
  2000年   423篇
  1999年   294篇
  1998年   187篇
  1997年   150篇
  1996年   128篇
  1995年   125篇
  1994年   148篇
  1993年   132篇
  1992年   200篇
  1991年   222篇
  1990年   203篇
  1989年   219篇
  1988年   209篇
  1987年   191篇
  1986年   232篇
  1985年   208篇
  1984年   161篇
  1983年   172篇
  1982年   116篇
  1981年   126篇
  1980年   87篇
  1979年   131篇
  1978年   76篇
  1977年   76篇
  1976年   70篇
  1974年   76篇
  1973年   66篇
  1972年   67篇
  1970年   47篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Understanding competing theories of negotiation   总被引:1,自引:0,他引:1  
  相似文献   
962.
963.
964.
965.
966.
967.
Results obtained from three commercial immunoassay kits, Abuscreen, TDx, and EMIT, commonly used for the initial test of urine cannabinoids (and metabolites) were correlated with the 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (9-THC-COOH) concentration as determined by GC/MS. Correlation coefficients obtained based on 26 (out of 1359 total sample population) highly relevant samples, are 0.601 and 0.438 for Abuscreen and TDx. Correlation coefficients obtained from a parallel study on a different set of 47 (out of 5070 total sample population) highly relevant specimens are 0.658 and 0.575 for Abuscreen and Emit. The immunoassay concentration levels, that correspond to the commonly used 15 ng/ml GC/MS cutoff value for 9-THC-COOH, as calculated from the regression equations are 82 ng/ml and 75 ng/ml for TDx and EMIT and 120 ng/ml and 72 ng/ml for Abuscreen manufactured at two different time periods. The difference of these calculated corresponding concentrations provides quantitative evidence of the reagent specificity differences.  相似文献   
968.
Hazards of mattresses, beds and bedding in deaths of infants   总被引:2,自引:0,他引:2  
Of 52 infants who had died suddenly and were referred to autopsy, nine had lain on adult water beds for the first time; five had died as a result of accidents; two had died on water beds; two were in beds with widely spaced slats; and one had died as a result of strangulation. Three deaths were due to overlying. Three other infants had been placed on sheepskin rugs for the first time and were found dead shortly thereafter. These infants ranged in age from 2 to 9 months, except for a severely mentally retarded nine-year-old with spastic paraplegia. We believe that a general warning should be issued concerning water beds and that soft bedding should not be used for infants. Infants should not be placed unattended or left to sleep on water beds; only beds recommended for infants should be used. Overlying of a young infant is most likely to occur on a water bed, or if the parent is obese or has consumed alcohol.  相似文献   
969.
970.
The external beveling caused by an entrance gunshot wound to the skull has not been completely explained, but the mechanism is probably a combination of several factors including the angle of shot, twisting force of a rotating bullet, blow-back effect, velocity, shape and size of the bullet, outspread of the kinetic energy from the bullet, and resistance of the skull.  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