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   13661篇
  免费   1327篇
各国政治   550篇
工人农民   470篇
世界政治   1058篇
外交国际关系   398篇
法律   9902篇
中国共产党   1篇
中国政治   96篇
政治理论   2422篇
综合类   91篇
  2021年   63篇
  2020年   372篇
  2019年   390篇
  2018年   451篇
  2017年   529篇
  2016年   532篇
  2015年   474篇
  2014年   499篇
  2013年   1502篇
  2012年   336篇
  2011年   453篇
  2010年   584篇
  2009年   555篇
  2008年   333篇
  2007年   323篇
  2006年   429篇
  2005年   318篇
  2004年   298篇
  2003年   304篇
  2002年   276篇
  2001年   477篇
  2000年   386篇
  1999年   330篇
  1998年   180篇
  1997年   166篇
  1996年   132篇
  1995年   162篇
  1994年   172篇
  1993年   134篇
  1992年   235篇
  1991年   251篇
  1990年   240篇
  1989年   244篇
  1988年   231篇
  1987年   194篇
  1986年   215篇
  1985年   240篇
  1984年   235篇
  1983年   196篇
  1982年   154篇
  1981年   139篇
  1980年   138篇
  1979年   155篇
  1978年   96篇
  1977年   82篇
  1976年   73篇
  1975年   75篇
  1974年   81篇
  1973年   68篇
  1972年   57篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
The population-adjusted rate of teenage suicide in King County, Washington, was reviewed for the 26 years from 1959 to 1984. For the entire period, the rate did not change significantly. An abrupt change did occur during the middle of this period, but, for reasons discussed in the text, this may well represent a change in procedures and philosophy of death certification rather than a real change in rate. Reasons for the apparent discrepancy with national statistics are discussed.  相似文献   
53.
54.
55.
56.
In the statistical interpretation of forensic glass evidence it is standard practice to make the assumption of homogeneity of the refractive index (RI) of the source glass, or of localized homogeneity. However, the work of Locke and Hayes showed that, for toughened windscreen glass, this assumption might not be true. This work is well cited, but there appears to have been little follow-on published research. Furthermore, the toughening process is something known to affect the refractive index, and is a process that float glass does not undergo. Float glass is a major component of casework in New Zealand and for that reason it would be interesting to know whether the findings of Locke and Hayes apply when dealing with float glass. In this paper we describe an experiment similar to that of Locke and Hayes, systematically examining the variation of RI in a pane of float window glass. It was found that, although there were no systematic differences in refractive index, there were observable differences across the pane.  相似文献   
57.
In many countries it is left to the discretion of the court to accept or reject conclusions based on sampling procedures as applied to the total drug exhibit. As an alternative to this subjective approach, a statistical basis is presented using binomial and hypergeometric distributions to determine a lower limit for the proportion of units in a population which contains a drug, at a given confidence level. A method for calculating the total weight of a drug present in a population within a given confidence interval is also presented. In the event of no failures (all units sampled contain a drug), a sample size of six or seven units is generally sufficient to state that a proportion of at least 0.70 of the population contains a drug at a confidence level of at least 90%. When failures do occur in the sample, point estimation is used as the basis for selecting the appropriate sample size.  相似文献   
58.
59.
Much attention has been paid to the nature of parent-adolescent relationships, with a frequent conclusion being that it is a time of marked disagreement between parents and their adolescents. However, other literature suggests that this time is not inherently conflictual. The purpose of this study was to examine agreement and disagreement between mothers, fathers, and adolescents on specific issues. Then, adolescent adjustment was assessed, and the degree to which it was a function of congruence with parents was examined. A modified version of the Issues Checklist was used to measure intrafamily agreement; the Revised Behavior Problem Checklist and the Harter Scale of Child's Actual Competence were completed by adolescents' social studies teachers to assess adolescent functioning. Relative to their parents, adolescents reported that they should make more decisions alone, while both mothers and fathers reported that decisions should be made jointly among all family members. Only father-adolescent congruence was found consistently to be related to adolescent functioning. Possible explanations for the present results and relevant issues pertaining to family agreement are discussed.  相似文献   
60.
Editors Note: This commentary touches on an aspect of technology transfer to the Third World that often is neglected: Can the technology recipients afford to use it? Although the authors focus on the economics of shrimp production by subsistence farmers, affordability is one of the major concomitant issues of transfer from developed to developing countries.  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