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   32151篇
  免费   1312篇
各国政治   1410篇
工人农民   1885篇
世界政治   1875篇
外交国际关系   1096篇
法律   20529篇
中国共产党   9篇
中国政治   149篇
政治理论   6352篇
综合类   158篇
  2021年   138篇
  2020年   509篇
  2019年   564篇
  2018年   1877篇
  2017年   1822篇
  2016年   1752篇
  2015年   703篇
  2014年   684篇
  2013年   2617篇
  2012年   833篇
  2011年   1530篇
  2010年   1622篇
  2009年   1277篇
  2008年   1384篇
  2007年   1370篇
  2006年   758篇
  2005年   682篇
  2004年   774篇
  2003年   661篇
  2002年   612篇
  2001年   884篇
  2000年   774篇
  1999年   620篇
  1998年   355篇
  1997年   276篇
  1996年   276篇
  1995年   284篇
  1994年   266篇
  1993年   257篇
  1992年   408篇
  1991年   444篇
  1990年   411篇
  1989年   409篇
  1988年   421篇
  1987年   401篇
  1986年   436篇
  1985年   453篇
  1984年   375篇
  1983年   359篇
  1982年   274篇
  1981年   246篇
  1980年   226篇
  1979年   307篇
  1978年   194篇
  1977年   153篇
  1976年   133篇
  1975年   153篇
  1974年   192篇
  1973年   146篇
  1972年   129篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
14.
15.
16.
This study aimed to expand the scope of previous research by assessing the effectiveness of soot-removal techniques on glass from petrol-bomb debris using methods of 1% and 2% sodium hydroxide (NaOH) solutions, ultrasonic bath and vacuum suction. Of particular interest were the 1% and 2% NaOH solutions applied to the soot-covered surfaces. Petrol bombs containing petrol or a 50:50 mix of petrol and motor oil were exploded and the debris was collected for analysis. Favourable results were found to varying degrees using each of the soot-removal methods with the 1% and 2% NaOH wash solutions, being the most useful. The 2% NaOH solution also proved successful as a soak to loosen and remove heavy contamination of soot and accelerants without damaging the finger mark beneath. This study also found that recovery of finger marks in blood from beneath soot using the 2% NaOH solution was possible. Finger marks were also applied to glass bottles with plastic adhesive labels, and providing the fire damage is not too great marks were also retrievable. Results from this study lead to the conclusion that the NaOH wash solution is ideally suited for soot removal to reveal latent and blood-contaminated marks both within the laboratory and at crime scenes.  相似文献   
17.
18.
The lungs of 79 children who had died between the ages of 1 week and 2 years old were histologically examined. 59 of these children could be categorized as cases of Sudden Infant Death because of the history and postmortem findings. In the remaining 20 cases a definite cause of death could be established. This is the same collective on which the histological investigations of the lymphatic tissue has been carried out. Morphological changes which are typical for a virus pneumonia were found in a substantially higher frequency in the cases of Sudden Infant Death than in the control cases. The validity of these findings and their possible significance for the cause of death are discussed.  相似文献   
19.
Restriction fragment length polymorphism (RFLP) analysis for the purpose of individualization is now being used in casework in the People's Republic of China. This report describes the use of the multilocus minisatellite probe 33.15 to solve three cases, including two homicides and a rape. In the third case, fetal tissue was analyzed to prove that the alleged rapist was, in fact, the father. In each case, analysis of deoxyribonucleic acid (DNA) resulted in a positive match. The probability of chance association of the DNA fingerprint was calculated as 5.6 x 10(-12), which is similar to the figures reported in the literature.  相似文献   
20.
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