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   14794篇
  免费   421篇
  国内免费   1篇
各国政治   788篇
工人农民   512篇
世界政治   974篇
外交国际关系   623篇
法律   8442篇
中国共产党   143篇
中国政治   348篇
政治理论   2855篇
综合类   531篇
  2020年   178篇
  2019年   194篇
  2018年   259篇
  2017年   289篇
  2016年   289篇
  2015年   229篇
  2014年   281篇
  2013年   1501篇
  2012年   348篇
  2011年   404篇
  2010年   419篇
  2009年   428篇
  2008年   468篇
  2007年   497篇
  2006年   523篇
  2005年   393篇
  2004年   323篇
  2003年   351篇
  2002年   325篇
  2001年   519篇
  2000年   407篇
  1999年   375篇
  1998年   193篇
  1997年   167篇
  1996年   141篇
  1995年   142篇
  1994年   146篇
  1993年   148篇
  1992年   234篇
  1991年   304篇
  1990年   272篇
  1989年   274篇
  1988年   264篇
  1987年   305篇
  1986年   283篇
  1985年   282篇
  1984年   258篇
  1983年   249篇
  1982年   175篇
  1981年   180篇
  1980年   150篇
  1979年   208篇
  1978年   153篇
  1977年   124篇
  1976年   119篇
  1975年   134篇
  1974年   148篇
  1973年   142篇
  1972年   104篇
  1971年   96篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
821.
822.
Most research on self-handicapping has focused on adults. Only a few studies have examined self-handicapping in adolescents or the particular characteristics of the family environment that are associated with self-handicapping. Adolescents (N = 141) and their mothers completed a series of questionnaires assessing adolescent self-handicapping, adolescent dysphoria, and parenting variables in mothers, including parenting styles (care and overprotection) and parenting stress due to situational variables, parent–child dysfunctional interactions, and behavioral characteristics of the child. Results showed (a) that self-handicapping was positively related to age in girls, but not in boys, (b) that there was a strong relation between self-handicapping and dysphoria in both boys and girls, (c) that mother-rated care negatively predicted self-handicapping in girls beyond the effects due to girls' dysphoria, and (d) that maternal care moderated the relationship between self-handicapping and dysphoria in boys. Maternal care and depressive affect in young persons are independently related to self-handicapping behaviors in adolescents. Results are discussed in terms of implications for the hypothesized etiology of self-handicapping.  相似文献   
823.
824.
825.
826.
DNA contamination by examination instruments   总被引:1,自引:0,他引:1  
Using DNA-analysis systems in forensic examination, conditions without any (iatrogenic) contamination are necessary for analysis of evidence. Failing these conditions a contamination is possible and interpretation of the results may be difficult. Our experiments demonstrated a relevant transfer of DNA-material if contaminated instruments were used.  相似文献   
827.
A method is presented for the numerical analysis of sex differences in size and shape of the proximal humeral outlines using elliptical Fourier functions (EFFs). A skeletal sample consisting of right and left humeri pairs of 69 individuals, 36 males and 33 females, was used. The proximal superior view in the plane of the proximo-distal axis of each humerus was photographed and then 54 boundary points were located on the two-dimensional outline tracings. These points were digitized and used to compute EFFs with 27 harmonics. From the EFFs, a set of expected points on the proximal humeral outline was generated using the centroid as an origin. Superimposition of the male and female outlines on this centroid provided a detailed picture of the relative sex differences in size and shape with respect to that center. The bounded area of the proximal humeral outline showed statistically significant sex differences. Additionally, statistical results of the amplitudes derived from the "area-standardized" EFFs and visual assessments of the mean outline plots indicated significant sex differences in shape of the proximal humeral outlines. Focusing on localized regional differences, the greater tubercle was located more postero-medially and the lesser tubercle was located more anteriorly in the males compared to the females. Sex determinations from the proximal humeri were also examined with discriminant functions based on the amplitudes, which represent shape characteristics of the outline, and the hounded area. Using a cross-validation method, predictions of the percentages of cases correctly classified with the discriminant functions were ranged from 92.8% to 95.7% for the right and left humeral data. These results suggest that differences in size and shape of the proximal humeral outlines may be better predictors of sex when compared with conventional measurements of the humerus.  相似文献   
828.
The purpose of the present investigation was to test the accuracy of a new scoring system in recording tooth wear for age estimation. The material consisted of dental stone casts of 383 volunteers who had sound premolars and molars with normal occlusion. The degree of occlusal wear for all premolar and molar teeth was scored with the new system. The high intra- and inter-examiner concordances showed that the new score system was very reliable. The degree of tooth wear showed a significant positive correlation with age in each and every examined tooth of both males and females. Tooth wear scores of males were higher than those of females. Calculating tables for age estimation were designed and the accuracy of age estimation was obtained with the General Linear Models procedures. Our system could provide estimation of an individual's age within +/-3 years in 42.4% of males and 49.4% of females, within +/-5 years in 61.8% of males and 63.3% of females. When the subjects were divided into two age groups and data were re-treated, the accuracy of age estimation was increased. Collectively, it was shown that our new system for scoring tooth wear is a reliable and accurate method for age estimation.  相似文献   
829.
Postmortem redistribution of morphine and its metabolites   总被引:2,自引:0,他引:2  
The postmortem redistribution of morphine, morphine-3-glucuronide, morphine-6-glucuronide and total morphine was assessed in 40 heroin-related deaths. In blood taken from subclavian, heart, and femoral regions, concentrations of morphine and its metabolites were similar. While there was a trend for higher concentrations in heart blood, when compared with femoral or subclavian blood, this was not significant. There was also no significant difference in concentrations between admission and autopsy blood in which the postmortem interval was on average 59 h. From our observations, significant postmortem redistribution of morphine and its metabolites seems unlikely.  相似文献   
830.
Our laboratory was asked to help with the rehydration of mummified human fingertips that had been removed from a recently deceased, unidentified female. Using a solution that was found in the archeological literature, we were able to successfully rehydrate dermal tissues to the extent that fingerprints could be taken. We believe that this solution, which until now has not been described in the forensic literature, is effective, affordable, and relatively easy to produce and use.  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