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   1146篇
  免费   55篇
各国政治   60篇
工人农民   71篇
世界政治   90篇
外交国际关系   92篇
法律   610篇
中国共产党   1篇
中国政治   18篇
政治理论   257篇
综合类   2篇
  2023年   12篇
  2022年   15篇
  2021年   39篇
  2020年   41篇
  2019年   51篇
  2018年   54篇
  2017年   55篇
  2016年   55篇
  2015年   41篇
  2014年   51篇
  2013年   196篇
  2012年   55篇
  2011年   47篇
  2010年   25篇
  2009年   42篇
  2008年   36篇
  2007年   51篇
  2006年   33篇
  2005年   19篇
  2004年   32篇
  2003年   24篇
  2002年   23篇
  2001年   19篇
  2000年   19篇
  1999年   12篇
  1998年   9篇
  1997年   11篇
  1996年   15篇
  1995年   12篇
  1994年   9篇
  1993年   9篇
  1992年   12篇
  1991年   9篇
  1990年   8篇
  1989年   9篇
  1988年   7篇
  1987年   5篇
  1986年   2篇
  1985年   2篇
  1984年   8篇
  1983年   2篇
  1982年   3篇
  1981年   2篇
  1979年   2篇
  1978年   3篇
  1977年   4篇
  1970年   1篇
  1969年   3篇
  1967年   1篇
  1966年   1篇
排序方式: 共有1201条查询结果,搜索用时 15 毫秒
871.
It is estimated that on a single night in January 2009, there were 643,067 sheltered and unsheltered homeless people in America (The 2009 Annual Homeless Assessment Report to Congress 2010). The Obama administration recently published “Opening Doors,” the first federal plan to prevent and end homelessness. We argue that the strategy is based on a partial evidence base that raises questions about the potential of the strategy to meet its goals. In order to inform future iterations of the plan, data from 682 young adults (aged 18–27 years old; mean = 22.13 years old) who participated in the National Longitudinal Study of Adolescent Health were used to examine whether there is a typologys of young adults with a history of homelessness; one of the priority groups in the strategy. A priori selected variables previously associated with lifetime homelessness in non-random samples were mapped to survey items. Data were analyzed using cluster analysis. Comparisons were conducted with a randomly selected “never-homeless” sample from the same study. The cluster analysis revealed four subgroups. It appears that the Federal Plan currently prioritizes homelessness risk factors associated with two subgroups: the Young Offenders subgroup and the Abused Depressed subgroup. The needs of two other subgroups are not fully addressed: the Childhood Adversity subgroup and the Vulnerable African-American subgroup. The authors offer guidance on future directions for homelessness policy relevant to young adults.  相似文献   
872.
Territorial autonomy is one aspect of power-sharing in multi-ethnic societies. Nevertheless, the multi-ethnic countries of Central and Eastern Europe are still among the most centralised in the European Union. This article analyses the failure of any attempts to establish (symmetric) federalism or (asymmetric) autonomy, creating self-governed regions by the Hungarian minorities in Romania and Slovakia. The analysis focuses on the positions of the main parties of the ethnic majorities and the Hungarian minority parties in the two countries. In both cases, the parties representing the Hungarian minorities have favoured territorial autonomy along ethnic lines, but this demand has been rejected by the parties of the ethnic majority. Against the historical legacy of unstable borders, the parties of the ethnic majority argue that territorial autonomy or federalisation might be a first step for a revisionist agenda and separatism. Instead, supported by the European integration, the parties have been able to agree on decentralisation as a half-hearted compromise.  相似文献   
873.
874.
875.
876.
877.
A highly sensitive screening method based on high performance liquid chromatography atmospheric pressure ionization mass spectrometry (HPLC-API-MS) has been developed for the analysis of 21 nitroaromatic, nitramine and nitrate ester explosives, which include the explosives most commonly encountered in forensic science. Two atmospheric pressure ionization (API) methods, atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI), and various experimental conditions have been applied to allow for the detection of all 21 explosive compounds. The limit of detection (LOD) in the full-scan mode has been found to be 0.012-1.2 ng on column for the screening of most explosives investigated. For nitrobenzene, an LOD of 10 ng was found with the APCI method in the negative mode. Although the detection of nitrobenzene, 2-, 3-, and 4-nitrotoluene is hindered by the difficult ionization of these compounds, we have found that by forming an adduct with glycine, LOD values in the range of 3-16 ng on column can be achieved. Compared with previous screening methods with thermospray ionization, the API method has distinct advantages, including simplicity and stability of the method applied, an extended screening range and a low detection limit for the explosives studied.  相似文献   
878.
The FearID research project is aimed at the individualisation of earprints for the purpose of forensic research. The study presented here was carried out within the framework of this project. It intends to combine a review of what is known from literature on the classification and individualisation of earprints with results from a preliminary study of earprints. Possibilities for, and limitations to, the use of earprints in forensic investigation are addressed. Differences between eliminating a suspect, placing a suspect at a crime scene, and linking crimes by prints left at different scenes are considered.  相似文献   
879.
The use of a QIAamp DNA Stool Mini Kit (QIAGEN) for extracting human nuclear DNA from feces samples is reported. This method employs a stool lysis buffer and a unique matrix (InhibitEX tablet) to remove PCR inhibitory substances specific to feces samples. DNA extracted from various amounts of stool and from stool samples exposed to different environmental impacts was successfully amplified and typed using the Profiler Plus Amplification Kit and ABI PRISM 310 Genetic Analyser.  相似文献   
880.
van Praag HM 《危机》2002,23(2):77-82
Over the past decades the rate of completed suicide has remained quite stable, whereas that of suicide attempts seems to have increased (to the extent it has been studied in defined regions). These are puzzling observations, since depression is the major suicide precursor and and since antidepressants have been increasingly used over the years in the treatment of depression. These observations have not attracted sufficient attention, possibly because they do not accord with consensus opinions about depression treatment in psychiatry today. This paper discusses a number of possible explanations that not only deserve, but are definitely in need of systematic investigation.  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