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   12548篇
  免费   394篇
各国政治   537篇
工人农民   476篇
世界政治   907篇
外交国际关系   399篇
法律   7631篇
中国政治   78篇
政治理论   2807篇
综合类   107篇
  2020年   143篇
  2019年   209篇
  2018年   256篇
  2017年   302篇
  2016年   281篇
  2015年   210篇
  2014年   261篇
  2013年   1252篇
  2012年   287篇
  2011年   349篇
  2010年   265篇
  2009年   340篇
  2008年   326篇
  2007年   346篇
  2006年   336篇
  2005年   320篇
  2004年   306篇
  2003年   323篇
  2002年   308篇
  2001年   458篇
  2000年   406篇
  1999年   328篇
  1998年   195篇
  1997年   156篇
  1996年   164篇
  1995年   165篇
  1994年   163篇
  1993年   153篇
  1992年   252篇
  1991年   266篇
  1990年   261篇
  1989年   261篇
  1988年   246篇
  1987年   238篇
  1986年   270篇
  1985年   272篇
  1984年   245篇
  1983年   225篇
  1982年   158篇
  1981年   134篇
  1980年   121篇
  1979年   155篇
  1978年   90篇
  1977年   114篇
  1976年   101篇
  1975年   74篇
  1974年   92篇
  1973年   87篇
  1972年   80篇
  1971年   69篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
A method was developed to screen for pepper spray residue using instruments and methods other than those techniques commonly employed to analyze chemical residue (i.e.. gas chromatography mass spectrometry-GCMS or liquid chromatography mass spectrometry-LCMS). The method employed gas chromatography (GC), thin layer chromatography (TLC), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to screen for dried pepper spray stains. Pepper sprays from nine different manufacturers were investigated. Capsaicin and dihydrocapsaicin were identified and unique IR reflectance spectra are presented. An additional five compounds were presumptively found. Results showed that a particular stain could be characterized as a pepper-based stain.  相似文献   
952.
Suicides due to fall from height in Geneva from 1991 to 2000 were reviewed. Scene investigations, autopsy findings, psychiatric histories, and toxicology results were examined. There were 197 of these suicides, an incidence of five cases per 100,000 inhabitants per year or one fourth of all suicides in Geneva per year. Autopsies were performed on 33%, the rest had external examinations. Of the victims, 56% were female and 44% were male. The age distribution peaked at 20-29 years in men and 60-69 years in women. Most of the victims jumped from their home, the range of 2 to 7 stories being the most frequent height. Major injury sites, in decreasing frequency, were the thorax, abdomen, skull, vertebrae, pelvis and limbs. Psychiatric illness was reported in 38% of the cases. Toxicological analysis was performed in 25% of the cases and showed that the main drugs present were benzodiazepines, cannabis and antidepressant.  相似文献   
953.
Supraphysiologic doses of testosterone are associated with increased aggression that is hypothesized to be a function of testosterone serum concentrations, mood, and personality. The study attempted to characterize this relationship among weightlifters who were users (n = 10) and nonusers (n = 18) of anabolic steroids. Participants were interviewed using the Modified Mania Rating Scale and Hamilton Rating Scale for Depression to assess mood, the Buss-Durkee Hostility Inventory (BDHI) and Point Subtraction Aggression Paradigm (PSAP) to assess aggression, and the Personality Disorder Questionnaire (PDQ-R) to assess personality. Blood samples were obtained for the determination of total, free, and weakly bound testosterone. Comparisons of continuous variables between testosterone users and non-users were performed with a parametric (unpaired t-test) or non-parametric (Mann-Whitney) test where appropriate. Correlations with testosterone were examined separately for testosterone users and non-users, using Spearman rank correlation. The subjective (BDHI) and objective (PSAP) assessments of aggression found that supranormal testosterone concentrations were associated with increased aggression. However, the PDQ-R results suggest that this finding was confounded by the personality disorder profile of the steroid users, because steroid users demonstrated Cluster B personality disorder traits for antisocial, borderline, and histrionic personality disorder.  相似文献   
954.
The presence of cocaine in illicit drug samples is still being determined in some laboratories using spot tests and microcrystal tests. Seventeen chemical species were tested using three different spot tests (Wagner, Marquis, and cobalt thiocyanate followed by stannous chloride reactions) and two microcrystal tests (gold chloride and platinic chloride) to determine whether the results could be differentiated from the results of these tests on cocaine. The data obtained indicated that nine of the 17 compounds gave results similar to those from cocaine using the three spot tests, but that the results from microcrystal testing allowed for differentiation of all nine compounds from cocaine.  相似文献   
955.

Introduction

Introduction to special issue on professional insecurities  相似文献   
956.

Commentary

Commentaries on Brunner and Willards professional insecurities  相似文献   
957.
Subject Acquisition for Web-Based Surveys   总被引:1,自引:0,他引:1  
  相似文献   
958.
Sweden's new multipillar pension system includes a system of mandatory fully funded individual accounts. The Swedish system offers contributors more than 600 fund options from a variety of private-sector fund managers. However, in the most recent rounds of fund choice, more than 90 percent of new labor market entrants have not made an active choice of funds and thus have ended up in a government-sponsored default fund. The Swedish system offers a number of lessons about implementing a mandatory individual account tier. Centralized administration keeps administrative costs down but requires considerable lead time. A very large number of fund options are likely to be offered unless strong entry barriers are in place. Engaging new labor market entrants in fund choice is likely to be difficult. A significant percentage of those making an active fund choice may choose funds that are very specialized and risky. Finally, special care must be devoted to designing a default fund and continual consumer communication.  相似文献   
959.
Corliss R 《Time》2001,157(16):54-63
  相似文献   
960.
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