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   1748篇
  免费   73篇
各国政治   113篇
工人农民   118篇
世界政治   129篇
外交国际关系   92篇
法律   880篇
中国政治   50篇
政治理论   431篇
综合类   8篇
  2023年   19篇
  2022年   10篇
  2021年   16篇
  2020年   46篇
  2019年   66篇
  2018年   76篇
  2017年   64篇
  2016年   74篇
  2015年   42篇
  2014年   49篇
  2013年   274篇
  2012年   50篇
  2011年   60篇
  2010年   52篇
  2009年   56篇
  2008年   64篇
  2007年   64篇
  2006年   51篇
  2005年   54篇
  2004年   42篇
  2003年   43篇
  2002年   48篇
  2001年   39篇
  2000年   36篇
  1999年   34篇
  1998年   15篇
  1997年   23篇
  1996年   18篇
  1995年   24篇
  1994年   22篇
  1993年   21篇
  1992年   27篇
  1991年   24篇
  1990年   17篇
  1989年   14篇
  1988年   15篇
  1987年   15篇
  1986年   15篇
  1985年   14篇
  1984年   11篇
  1983年   15篇
  1982年   9篇
  1981年   14篇
  1980年   6篇
  1979年   8篇
  1978年   11篇
  1977年   6篇
  1976年   5篇
  1974年   5篇
  1967年   5篇
排序方式: 共有1821条查询结果,搜索用时 15 毫秒
111.
Self-esteem and psychological symptoms were assessed in a sample of 1082 Chinese adolescents who responded to the Chinese versions of Coopersmith's Self-Esteem Inventory and the General Health Questionnaire. Three dimensions of self-esteem, interpreted as Family Acceptance/Rejection, Self-Depreciation, and Peer Affirmation/Disaffirmation, were found to relate substantially to general psychological symptoms and particularly to specific symptoms of anxiety, social dysfunction, and depression as reported by these adolescents. The implications of the relative importance of appraisal from internal feedback as sources of self-esteem as opposed to the external feedback from family and peers were discussed in relation to self-esteem enhancement in adolescents.Received his Ph.D. from the University of Western Ontario in 1978. His research interests include self-esteem, stress, coping, health and psychopathology.Received her Ph.D. from the University of South Dakota in 1983. Her research interests include stress, coping and health, and geriatric psychology.  相似文献   
112.
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   
113.
Like many other places in the world, Hong Kong has drink-driving legislation which prohibits a driver from having in his blood alcohol exceeding a prescribed limit while in control of a motor vehicle. The accuracy of measuring this alcohol concentration is obviously of prime concern as an erroneous result can avert the administration of justice. The common practice is to deduct all errors from the measured value and compare the deducted value with the prescribed limit, so that the benefit of all errors of the measurement is given to the driver. It is therefore important for any laboratory responsible for measuring blood alcohol concentrations to identify and quantify all errors associated with the measurement. The present study examined 900 blood alcohol determinations carried out by the Hong Kong Government Laboratory (HKGL) on cases of suspected drink driving. The determinations were performed by 5 different analysts with two different sets of instruments during 1995-1997. Statistical analysis indicated that the instruments had no bearing on the random error or variability and that even though analyst was a significant factor on variability, the deviation from the mean so caused was only 0.3% and of no practical significance. When the systematic error introduced by the tolerance limits of the certified alcohol standards (purchased from the Laboratory of Government Chemists, UK) was taken into account, the total uncertainty (random plus systematic errors) of an alcohol determination at 99.5% confidence level was found to be 4%. It is recommended that laboratories engaged in blood alcohol determination should adopt similar statistical treatment of their analytical results to find out the error and to ensure that the results are independent of analyst and instrument used.  相似文献   
114.
115.
116.
117.
A relatively simple, routine method has been described for the qualitative identification of flurazepam and its primary metabolite 7-chloro-1-(2-hydroxyethyl)-5-(2-fluorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one in urine. We have described two extractions and several identification procedures by which flurazepam and its primary urinary metabolite can be identified by TLC.  相似文献   
118.
119.
120.
Asphyxia, not an uncommon cause of sudden death, may result from numerous etiologies. Foreign-body aspiration and strangulation are 2 extrinsic causes. Airway obstruction may also be caused by laryngeal edema, asthma, infection, or anaphylaxis. Chronic causes of asphyxia include musculoskeletal diseases (eg, muscular dystrophy, amyotrophic lateral sclerosis), neurologic disorders (eg, myasthenia gravis, multiple sclerosis), respiratory disease (eg, emphysema, chronic bronchitis), or tumors. The manner of death in cases of asphyxiation may be natural, accidental, homicide, or suicide. For the death investigator, determining the cause and manner of death can often be quite challenging.We report here 2 cases of an esophageal fibrovascular polyp causing sudden asphyxial death, review of the literature, and discussion of other differential diagnoses in the case of asphyxial death.  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