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   1152篇
  免费   57篇
各国政治   58篇
工人农民   54篇
世界政治   102篇
外交国际关系   79篇
法律   636篇
中国共产党   2篇
中国政治   11篇
政治理论   229篇
综合类   38篇
  2023年   9篇
  2022年   9篇
  2021年   11篇
  2020年   41篇
  2019年   30篇
  2018年   46篇
  2017年   45篇
  2016年   45篇
  2015年   34篇
  2014年   41篇
  2013年   157篇
  2012年   53篇
  2011年   50篇
  2010年   47篇
  2009年   49篇
  2008年   59篇
  2007年   39篇
  2006年   46篇
  2005年   52篇
  2004年   37篇
  2003年   37篇
  2002年   29篇
  2001年   33篇
  2000年   30篇
  1999年   14篇
  1998年   19篇
  1997年   12篇
  1996年   10篇
  1995年   15篇
  1994年   10篇
  1993年   8篇
  1992年   4篇
  1991年   5篇
  1990年   5篇
  1989年   8篇
  1988年   7篇
  1986年   9篇
  1985年   3篇
  1983年   13篇
  1982年   5篇
  1981年   2篇
  1979年   3篇
  1978年   2篇
  1977年   2篇
  1976年   2篇
  1974年   5篇
  1973年   2篇
  1972年   3篇
  1971年   3篇
  1967年   3篇
排序方式: 共有1209条查询结果,搜索用时 15 毫秒
61.
The amphetamine derivative 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy" is a currently used or abused designer drug and fatalities are frequently encountered in forensic practice. However, the question remains open whether an MDMA blood level can be toxic or even potentially lethal. In order to provide insight in the interpretation of a detected MDMA concentration, the distribution of MDMA and its metabolite 3,4-methylenedioxyamphetamine (MDA) in various body fluids and tissues was studied and discussed in two different fatalities. Apart from peripheral blood samples (such as femoral and subclavian blood), various blood samples obtained centrally in the human body and several body fluids (such as vitreous humour) were examined. In addition, various tissues such as cardiac muscle, lungs, liver, kidneys, and brain lobes were analysed. In contrast to the peripheral blood levels, high MDMA and MDA levels were found in cardiac blood and the majority of the organs, except for the abdominal adipose tissue. The high concentrations observed in all lung lobes, the liver and stomach contents indicate that post-mortem redistribution of MDMA and MDA into cardiac blood can occur and, as a result, blood sampled centrally in the body should be avoided. Therefore, our data confirm that peripheral blood sampling remains "the golden standard". In addition, a distinct difference in peripheral blood MDMA concentrations in our two overdose cases was established (namely 0.271 and 13.508 microg/ml, respectively). Furthermore, our results suggest that, if a peripheral blood sample is not available and when putrefaction is not too pronounced, vitreous humour and iliopsoas muscle can be valuable specimens for toxicological analysis. Finally, referring to the various mechanisms of death following amphetamine intake, which can result in different survival times (e.g. cardiopulmonary complications versus hyperthermia), the anatomo-pathological findings and the toxicological results should be considered as a whole in arriving at a conclusion.  相似文献   
62.
In recent years, there has been a surge in patenting by Belgian universities. It appears that this increase can be attributed to growth of biotechnology, where there is a greater propensity to patent, to a desire on the part of universities to enhance commercialization through technology transfer offices (TTOs), and to effective collaboration between universities and government-sponsored research centers. Our qualitative analysis reveals that patent statistics could be a misleading indicator of an individual university's technological productivity, since many inventions are developed at universities, yet applied by other institutions.  相似文献   
63.
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   
64.
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   
65.
66.
67.
68.
当前大学生恋爱中不良倾向的分析与思考   总被引:5,自引:0,他引:5  
当前在大学生恋爱中存在的低龄化、休闲化、时尚化、体验化、实用化、“快餐化”和放纵化等不良倾向,对大学生的成长和成才构成了很大威胁。学校必须加强对大学生恋爱的教育、管理和指导。  相似文献   
69.
This article explores efforts to bridge multi-disciplinary research and policy engagement to tackle child poverty in the contexts of developing countries, based on the experiences of Young Lives, an international longitudinal policy-research project. It focuses on a case study involving the application of research evidence on child poverty to shape policy debates concerning Ethiopia's second-generation Poverty Reduction Strategy Paper (2006–2010). The discussion is situated within theoretical literature on the interface between knowledge, policy, and practice, which supports the conceptualisation of policy making as a non-linear dynamic process. It pays particular attention to the importance of understanding the political and policy contexts of Southern countries, rather than assuming that they should simply import Northern-derived models of advocacy. It concludes by identifying general lessons for translating research into social-policy change.  相似文献   
70.
The interpretation of bloodstain patterns at crime scenes has received increased attention in recent years. Important to an understanding of this is knowledge of the fundamentals of blood droplet formation and impact dynamics. A review of the literature reveals that a considerable amount of work has been done with aqueous drop dynamics. Workers in the forensic science area seem to have been unaware of this. In addition, some of the most important and comprehensive early work with blood droplet dynamics seems to have been forgotten. It is not cited in more recent publications dealing with bloodstain pattern interpretation. This literature is reviewed and discussed as well. The present study presents results of experiments with blood droplet dynamics and high-speed photographs of blood droplet impacts on stationary target surfaces. Some longstanding misconceptions of importance to forensic scientists engaged in crime scene reconstruction are discussed.  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