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   4544篇
  免费   166篇
各国政治   161篇
工人农民   145篇
世界政治   302篇
外交国际关系   167篇
法律   3101篇
中国共产党   2篇
中国政治   46篇
政治理论   735篇
综合类   51篇
  2023年   26篇
  2021年   33篇
  2020年   73篇
  2019年   73篇
  2018年   100篇
  2017年   115篇
  2016年   113篇
  2015年   90篇
  2014年   108篇
  2013年   379篇
  2012年   124篇
  2011年   147篇
  2010年   116篇
  2009年   115篇
  2008年   142篇
  2007年   107篇
  2006年   132篇
  2005年   128篇
  2004年   130篇
  2003年   123篇
  2002年   116篇
  2001年   209篇
  2000年   158篇
  1999年   114篇
  1998年   54篇
  1997年   50篇
  1996年   42篇
  1995年   58篇
  1994年   48篇
  1993年   57篇
  1992年   83篇
  1991年   88篇
  1990年   81篇
  1989年   70篇
  1988年   89篇
  1987年   83篇
  1986年   106篇
  1985年   109篇
  1984年   87篇
  1983年   85篇
  1982年   40篇
  1981年   37篇
  1979年   35篇
  1978年   34篇
  1975年   31篇
  1974年   49篇
  1972年   29篇
  1971年   31篇
  1970年   30篇
  1968年   32篇
排序方式: 共有4710条查询结果,搜索用时 15 毫秒
971.
972.
The circumferences of the four intact cardiac valves were measured during 397 coroner's autopsies using an obturator cone to assess the value of this measurement in the postmortem diagnosis of cardiac disease. Valve sizes of cases with cardiac and noncardiac causes of death were compared using logistic regression to assess the effects of confounding variables including sex, age, height, build and the presence of chronic obstructive airways disease. Mitral valve enlargement was found to be significantly associated with cardiac death, as were build, age, and sex. Measurement of the mitral valve at autopsy can help distinguish cardiac from noncardiac causes of death.  相似文献   
973.
110 stab-cut skin wounds in 34 dead bodies as well as 38 stab-cut instruments were studied. Three morphologic types of traces left by blade edges of stab-cut instruments, i.e. puncture, microrupture and microcut, were established. Gross and micromorphology of each of these traces depends on the properties of blade edges of stab-cut instruments.  相似文献   
974.
Orosomucoid 1 phenotypes were detected in seminal plasma by isoelectric focusing and immunoprinting. The orosomucoid 1 phenotypes in seminal plasma correlated with the types found in the corresponding serum specimens. Semen stains stored for ten days could be typed for orosomucoid 1. The present work revealed that orosomucoid 1 is a useful genetic marker for the medicolegal grouping of semen stains.  相似文献   
975.
Muscle and adipose tissue from a total of 178 experimental bruises inflicted on sheep and aged from 1 to 72 h old were processed for light microscopic examination. Five observed histopathological features of inflammation and repair were scored semiquantitatively on a scale of 1-4 according to their degrees of change from the normal state. These data were evaluated mathematically using a Bayesian probability model designed for the purpose. The model was able to age bruises with an acceptable degree of accuracy only as either 1-20 h or 24-72 h old but within these constraints a degree of confidence in excess of 90% was achieved. The exact performance of the model depended on the nature and number of tissue samples examined but mathematical ageing was superior to interpretative ageing based on personal experience.  相似文献   
976.
977.
A discriminant function analysis of deciduous teeth to determine sex   总被引:3,自引:0,他引:3  
Studies of deciduous teeth have concluded that crown size differences in these teeth between males and females are not reliable sex discriminators, in contrast to such differences in permanent teeth. This study measured the mesiodistal and faciolingual crown diameters of all deciduous teeth, as well as those of the permanent first molars, of 162 children from the Burlington Orthodontic Growth Study, conducted earlier in Burlington, Ontario, Canada. All 40 deciduous tooth diameters (20 mesiolingual and 20 faciolingual) were significantly different between the sexes, as were the permanent tooth diameters. Using three to five measurements of deciduous teeth, discriminant analyses of several samplings of these children produced discriminant functions in which 76 to 90% of the holdout samples were correctly classified by sex. Combinations of deciduous and permanent measurements were used to classify 83 to 85% of the holdout samples correctly. When compared with published data on other sample populations, the Burlington group is the most dimorphic for deciduous teeth and is within the range of permanent tooth dimorphisms of other populations. The level of classification accuracy, when using discriminant analysis of the deciduous teeth, can approach the accuracy levels of analysis using the permanent teeth.  相似文献   
978.
979.
980.
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