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   11536篇
  免费   605篇
各国政治   511篇
工人农民   455篇
世界政治   946篇
外交国际关系   351篇
法律   7553篇
中国共产党   1篇
中国政治   64篇
政治理论   2206篇
综合类   54篇
  2021年   71篇
  2020年   223篇
  2019年   259篇
  2018年   273篇
  2017年   341篇
  2016年   327篇
  2015年   283篇
  2014年   290篇
  2013年   1123篇
  2012年   283篇
  2011年   341篇
  2010年   305篇
  2009年   326篇
  2008年   330篇
  2007年   304篇
  2006年   308篇
  2005年   293篇
  2004年   285篇
  2003年   264篇
  2002年   264篇
  2001年   490篇
  2000年   439篇
  1999年   310篇
  1998年   197篇
  1997年   157篇
  1996年   135篇
  1995年   130篇
  1994年   159篇
  1993年   148篇
  1992年   212篇
  1991年   232篇
  1990年   216篇
  1989年   226篇
  1988年   213篇
  1987年   201篇
  1986年   239篇
  1985年   224篇
  1984年   170篇
  1983年   173篇
  1982年   121篇
  1981年   129篇
  1980年   93篇
  1979年   133篇
  1978年   77篇
  1977年   77篇
  1976年   72篇
  1974年   75篇
  1973年   68篇
  1972年   66篇
  1970年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
The recent formation of a United Kingdom and Irish working group, the Body Fluids Forum (BFF), highlighted the need to investigate different working practices prior to any inter-laboratory comparison work and identification of best practice. Various dilutions of semen were seeded onto swabs and cloth samples for each BFF member laboratory to test using their standard techniques. The results showed that the detection of acid phosphatase on swabs is best achieved using direct testing rather than on an extract from the swab. Extraction methods for spermatozoa require a balance to be achieved between using a sufficient volume of water to ensure optimal release and minimal volume to ensure a concentrated extract. PSA tests were investigated and found to be more sensitive than Choline. DNA profiles were obtained from samples in which no spermatozoa had been detected during microscopic examination.  相似文献   
994.
Statement of Purpose: A decline in state-sponsored terrorism has caused many terrorist organizations to resort to criminal activity as an alternative means of support. This study examines terrorists' involvement in a variety of crimes ranging from motor vehicle violations, immigration fraud, and manufacturing illegal firearms to counterfeiting, armed bank robbery, and smuggling weapons of mass destruction. Special attention is given to transnational organized crime. Crimes are analyzed through the routine activity perspective and social learning theory. These theories draw our attention to the opportunities to commit crime and the criminal skills necessary to turn opportunity into criminality. Through these lenses, the research appraises the “successes” and “failures” of terrorists' engagement in crime. Because “failures” can result from law enforcement efforts to (1) interrupt criminal skill development, and/or (2) remove criminal opportunities via technologies and transportation systems, the research represents a best practices approach to the study and control of terrorism. This project was supported by Grant No. 2003-DT-CX-0002 awarded by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice. Points of view in this document are those of the author and do not necessarily represent the official position or policies of the U.S. Department of Justice.  相似文献   
995.
A case of fatal poisoning due to the combined effect of alcohol and gasoline following an automobile accident is described. Toxicological analyses by means of gas chromatography and gas chromatography-mass spectrometry permitted the identification and quantitation of alcohol and several hydrocarbons in the heart blood and in the gas in the lung. Great variation was found in the estimates of blood gasoline concentration, depending on which of six constituents of gasoline was chosen for quantitation. The cause of this variation is discussed, together with the possible mechanisms leading to death.  相似文献   
996.
997.
The limited literature on the topic speculates that the rate of ADHD would be higher among incarcerated youth than found in the general population. However, to our knowledge no such published figures exist for juveniles in the United States. This study investigates the likelihood of ADHD diagnosis among 453 incarcerated youth and compares and contrasts a variety of demographic, social, educational, psychological, and criminal characteristics to the general literature on ADHD. Both similarities and differences are reported. This project was supported by Grant #99-RT-VX-K020 awarded by the National Institute of Justice. Points of view in this document are those of the author and do not necessarily represent the official position or policies of the U.S. Department of Justice. An early version of the paper was presented at the annual meeting of the Academy of Criminal Justice Science in Chicago, Illinois.  相似文献   
998.
Microscopical study on estimation of time since death in skeletal remains   总被引:1,自引:0,他引:1  
For the purpose of estimating time since death in skeletal remains, postmortem changes in human compact bones were examined by microradiography and electron microscopy. The UV-fluorescence of the peripheral zone of compact bone was also examined by microscopic spectrophotometry. Microradiographic examination revealed no morphological changes in bones left in the open air for long periods, except one of 15 years since death. In bones left in the soil, vacuoles of 5-10 microns diameter, which contained a honeycomb-like structure formed by small vacuoles of 0.5-1 microns diameter, were found in the peripheral zone of the substantia compacta approximately 5 years since death, and in bones of 6 years or more, this change extended to the mid-zone. In bones left in the sea for 4-5 years, vacuoles of 5-10 microns diameter were observed in the outer peripheral zone of the substantia compacta. The relative intensity of UV-fluorescence in bones dwindled with time since death and the correlation coefficient was considerably high.  相似文献   
999.
Several forms of expert forensic science evaluations exist that rely at least in part on the subjective opinion of the examiner. Human hair identification is one such examination. This paper considers possible sources of influence or bias that may be responsible for examiner errors. Data are reported of an experiment that compares the conventional examination procedure (known versus questioned samples) against an alternative procedure (a lineup of samples) designed to limit the influence of factors that contribute to error. The altenative procedure produced fewer incorrect conclusions (3.8%) than the conventional procedure (30.4%).  相似文献   
1000.
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