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   934篇
  免费   57篇
各国政治   58篇
工人农民   46篇
世界政治   58篇
外交国际关系   69篇
法律   397篇
中国政治   12篇
政治理论   339篇
综合类   12篇
  2023年   9篇
  2022年   5篇
  2021年   8篇
  2020年   25篇
  2019年   26篇
  2018年   32篇
  2017年   36篇
  2016年   50篇
  2015年   26篇
  2014年   39篇
  2013年   128篇
  2012年   37篇
  2011年   36篇
  2010年   29篇
  2009年   29篇
  2008年   22篇
  2007年   26篇
  2006年   41篇
  2005年   39篇
  2004年   29篇
  2003年   39篇
  2002年   34篇
  2001年   21篇
  2000年   16篇
  1999年   14篇
  1998年   16篇
  1997年   19篇
  1996年   4篇
  1995年   9篇
  1994年   6篇
  1993年   15篇
  1992年   5篇
  1991年   8篇
  1990年   9篇
  1989年   8篇
  1988年   9篇
  1987年   4篇
  1986年   7篇
  1985年   10篇
  1983年   5篇
  1981年   6篇
  1980年   8篇
  1979年   7篇
  1978年   7篇
  1977年   6篇
  1976年   3篇
  1975年   4篇
  1974年   4篇
  1973年   4篇
  1972年   3篇
排序方式: 共有991条查询结果,搜索用时 31 毫秒
241.
242.
This paper compares the quality and use of regulatory analysis accompanying economically significant regulations proposed by US executive branch agencies in 2008, 2009, and 2010. We find that the quality of regulatory analysis is generally low, but varies widely. Budget regulations, which define how the federal government will spend money or collect revenues, have much lower‐quality analysis than other regulations. The Bush administration's “midnight” regulations finalized between Election Day and Inauguration Day, along with other regulations left for the Obama administration to finalize, tended to have lower‐quality analysis. Most differences between the Bush and Obama administrations depend on agencies' policy preferences. More conservative agencies tended to produce better analysis in the Obama administration, and more liberal agencies tended to do so in the Bush administration. This suggests that agencies more central to an administration's policy priorities do not have to produce as good an analysis to get their regulations promulgated.  相似文献   
243.
How can scientists acquire an adequate level of knowledge on phenomena whose actors actively conceal their activities? Social phenomena such as terrorism, sects, corruption, Mafia organizations, drug dealers, or government intelligence agencies actively guard their secrecy, conceal their activities, decide who is allowed (not) to know, and have no interest in being observed or understood by others. The article discusses the consequences of researching difficult-access problems for doing multi-method research. In an ideal?Ctypical approach, we distinguish between social problems that can be easily accessed and those that are difficult to access or non-accessible. To distinguish the two, we define characteristics that eventually lead to the conclusion that scientific inquiry that follows the conventional paradigm of professionalism, transparency, and replicable research reaches its limits when confronted with the active resistance of phenomena that do not like to be observed, understood, or critically approached. From this flows, the necessity to think about interdisciplinary, collaborative, and investigative modes of research that come with various prices.  相似文献   
244.
245.
246.
247.
The federal budgeting process is now limited by deficit reduction policy constraints. This article examines the FY 1995 budget requests within the context of long term budget trends, changes in the federal budget process, and the recently established political and fiscal budget constraints. It further examines enactment of the Omnibus Budget Enforcement Act of 1993, the policy changes it contained, and its further tinkering with the process of budgeting. Finally the article evaluates the first budgeting process of the Clinton administration and their initiatives in deficit reduction following these policy constraints.  相似文献   
248.
Following a brief review of recent criticism of technical cooperation as an instrument for capacity building in sub-Saharan Africa, this article examines current strategies for addressing the professional staff retention problem within African governments, and for making the market for technical cooperation more effective by allowing greater substitution of national experts for expatriate experts in project design and implementation. In order to strengthen and effectively use scarce local expertise, while avoiding its diversion to donor-financed projects, the article proposes capacity-building strategies aimed at the development of national or regional markets for development analysis and management expertise in sub-Saharan Africa.  相似文献   
249.
Illicitly produced heroin is commonly cut with carbohydrates to increase bulk. The analysis of these solutes is important for legal and intelligence purposes. A capillary electrophoresis (CE) method was developed for the qualitative analysis of dextrose, lactose, sucrose, inositol, and mannitol in heroin exhibits. For this method, a 64 cm (55.5 cm to detector window) by 50 mum capillary was used with the Agilent Basic Anion Buffer modified to pH 12.1. This separation was performed at 25 degrees C with a voltage of 20 kV and indirect detection with 2,6-pyridinedicarboxylic acid as the visualization reagent. The methodology is also applicable for the screening of inorganic and organic anions using indirect detection, and acidic adulterants using direct detection. For a run time of 13 min, the relative standard deviation (n = 6) of the methodology was better than 0.36% for migration times and less than 2.6% for corrected peak areas. For the analysis of carbohydrates and acidic adulterants in seized heroin, excellent agreement was obtained between CE and nuclear magnetic resonance spectroscopy.  相似文献   
250.
This study presents a new animal model, the Large White Pig, which was tested for studying cannabinoids metabolism. The first step has focused on determination of plasma kinetics after injection of Delta(9)-tetrahydrocannabinol (THC) at different dosages. Seven pigs received THC by intravenous injections (50, 100 or 200 microg/kg). Plasma samples were collected during 48 h. Determination of cannabinoids concentrations were performed by gas chromatography/mass spectrometry. Results showed that plasma kinetics were comparable to those reported in humans. Terminal half-life of elimination was 10.6 h and a volume of distribution of 32 l/kg was calculated. In a second step, this model was used to determine the kinetic profile of cannabinoids distribution in tissues. Eight Large White male pigs received an injection of THC (200 microg/kg). Two pigs were sacrificed 30 min after injection, two others after 2, 6 and 24 h. Different tissues were sampled: liver, kidney, heart, lung, spleen, muscle, fat, bile, blood, vitreous humor and several brain areas. The fastest THC elimination was noted in liver tissue, where it was completely eliminated in 6 h. THC concentrations decreased in brain tissue slower than in blood. The slowest THC elimination was observed for fat tissue, where the molecule was still present at significant concentrations 24 h later. After 30 min, THC concentration in different brain areas was highest in the cerebellum and lowest in the medulla oblongata. THC elimination kinetics noted in kidney, heart, spleen, muscle and lung were comparable with those observed in blood. 11-Hydroxy-THC was only found at high levels in liver. THC-COOH was less than 5 ng/g in most tissues, except in bile, where it increased for 24 h following THC injection. This study confirms, even after a unique administration, the prolonged retention of THC in brain and particularly in fat, which could be at the origin of different phenomena observed for heavy users such as prolonged detection of THC-COOH in urine or cannabis-related flashbacks. Moreover, these results support the interest for this animal model, which could be used in further studies of distribution of cannabinoids in tissues.  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