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   10567篇
  免费   549篇
各国政治   420篇
工人农民   362篇
世界政治   821篇
外交国际关系   299篇
法律   7124篇
中国共产党   1篇
中国政治   55篇
政治理论   1993篇
综合类   41篇
  2021年   60篇
  2020年   195篇
  2019年   235篇
  2018年   234篇
  2017年   291篇
  2016年   299篇
  2015年   246篇
  2014年   270篇
  2013年   998篇
  2012年   236篇
  2011年   305篇
  2010年   288篇
  2009年   300篇
  2008年   290篇
  2007年   257篇
  2006年   280篇
  2005年   254篇
  2004年   250篇
  2003年   234篇
  2002年   243篇
  2001年   467篇
  2000年   422篇
  1999年   293篇
  1998年   181篇
  1997年   151篇
  1996年   125篇
  1995年   119篇
  1994年   146篇
  1993年   132篇
  1992年   197篇
  1991年   220篇
  1990年   203篇
  1989年   214篇
  1988年   205篇
  1987年   194篇
  1986年   232篇
  1985年   206篇
  1984年   160篇
  1983年   170篇
  1982年   114篇
  1981年   121篇
  1980年   87篇
  1979年   131篇
  1978年   76篇
  1977年   73篇
  1976年   69篇
  1974年   74篇
  1973年   67篇
  1972年   67篇
  1970年   47篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
Abstract: The Quantifiler® Duo DNA Quantification kit enables simultaneous quantification of human DNA and human male DNA as well as detection of inhibitors of PCR in a single real-time PCR well. Pooled human male genomic DNA is used to generate standard curves for both human (ribonuclease P RNA component H1) and human male (sex determining region Y) specific targets. A shift in the cycle threshold (CT) values for the internal positive control monitors the presence of PCR inhibitors in a sample. The assay is human specific and exhibits a high dynamic range from 0.023 to 50 ng/μL. In addition, the multiplex assay can detect as little as 25 pg/μL of human male DNA in the presence of a 1000-fold excess of human female DNA. The multiplex assay provides assessment of the DNA extract and guidance for the selection of the appropriate AmpFℓSTR® Amplification Kit to obtain interpretable short tandem repeat profiles.  相似文献   
902.
903.
904.
905.
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   
906.
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   
907.
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   
908.
909.
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   
910.
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   
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