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   1295篇
  免费   59篇
各国政治   67篇
工人农民   91篇
世界政治   105篇
外交国际关系   113篇
法律   674篇
中国共产党   1篇
中国政治   18篇
政治理论   274篇
综合类   11篇
  2023年   11篇
  2022年   19篇
  2021年   43篇
  2020年   48篇
  2019年   58篇
  2018年   64篇
  2017年   69篇
  2016年   61篇
  2015年   45篇
  2014年   66篇
  2013年   214篇
  2012年   59篇
  2011年   56篇
  2010年   37篇
  2009年   45篇
  2008年   42篇
  2007年   55篇
  2006年   37篇
  2005年   24篇
  2004年   30篇
  2003年   25篇
  2002年   30篇
  2001年   21篇
  2000年   22篇
  1999年   11篇
  1998年   10篇
  1997年   13篇
  1996年   14篇
  1995年   13篇
  1994年   8篇
  1993年   9篇
  1992年   12篇
  1991年   8篇
  1990年   8篇
  1989年   8篇
  1988年   7篇
  1987年   4篇
  1985年   4篇
  1984年   8篇
  1983年   3篇
  1982年   5篇
  1981年   3篇
  1980年   2篇
  1979年   2篇
  1978年   4篇
  1977年   5篇
  1970年   1篇
  1969年   3篇
  1967年   1篇
  1966年   1篇
排序方式: 共有1354条查询结果,搜索用时 0 毫秒
81.
The public choice literature contains little formal analysis of the bureaucratic choice of production modes — public or private — of publicly funded services. An important question to be addressed is why some governmental bodies choose to provide a publicly funded service with publicly owned and operated production units whereas other governmental bodies contract with private firms to provide the same publicly funded service. This paper is the first formal attempt to remedy this gap in the literature. We develop a theoretical explanation of the government decision maker's choice between public and private production modes based on utility maximizing behavior. We then examine empirically this choice employing logit analysis. The empirical results, which include several tests for robustness, confirm our theoretical explanation. The results are significant and suggest that non-monetary constraints are an important factor affecting this choice of production modes and that monetary constraints are less influential.  相似文献   
82.
83.
Forensic analysis of glass samples was performed in different laboratories within the NITE-CRIME (Natural Isotopes and Trace Elements in Criminalistics and Environmental Forensics) European Network, using a variety of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) systems. The main objective of the interlaboratory tests was to cross-validate the different combinations of laser ablation systems with different ICP-MS instruments. A first study using widely available samples, such as the NIST SRM 610 and NIST SRM 612 reference glasses, led to deviations in the determined concentrations for trace elements amongst the laboratories up to 60%. Extensive discussion among the laboratories and the production of new glass reference standards (FGS 1 and FGS 2) established an improved analytical protocol, which was tested on a well-characterized float glass sample (FG 10-1 from the BKA Wiesbaden collection). Subsequently, interlaboratory tests produced improved results for nearly all elements with a deviation of < 10%, demonstrating that LA-ICP-MS can deliver absolute quantitative measurements on major, minor and trace elements in float glass samples for forensic and other purposes.  相似文献   
84.
A new retrieval system for a 3D facial image database was designed and its reliability was experimentally examined. This system has two steps, firstly to automatically adjust the orientation of all 3D facial images in a database to that of the 2D facial image of a target person, and then to identify the facial image of the target person from the adjusted 3D facial images in the database using a graph-matching method. From the experimental study [M. Yoshino, K. Imaizumi, T. Tanijiri, J.G. Clement, Automatic adjustment of facial orientation in 3D face image database, Jpn. J. Sci. Tech. Iden. 8 (2003) 41-47], it is concluded that the software developed for the first step will be applicable to the automatic adjustment of facial orientation in the 3D facial image database. In 28 out of 110 sets (25.5%), the 3D image of the target person was chosen as the best match (from a database of 132 3D facial images) according to the similarity of the facial image characteristics based on the graph matching. The 3D facial image of the target person was ranked in the top of 10 of the database in 75 out of 110 sets (68.2%). These results suggest that this system is inadequate for the identification level, but may be feasible for screening method in a small database. It will be necessary to further pursue the possibility of realization of a facial image retrieval system for a large database such as suspects' facial images in future.  相似文献   
85.
86.
An HPLC-APCI-MS(/MS) method for the (trace) analysis of the most commonly encountered peroxide explosives, hexamethylenetriperoxidediamine (HMTD) and triacetonetriperoxide (TATP), has been developed. With this method, HMTD and TATP have been analyzed in the same run. (Pseudo-)molecular ions of these peroxides have been obtained as base peak under the same condition. A series of product ions was produced from these pseudo-molecular ions ([HMTD - 1]+ and [TATP + NH4]+) in the MS/MS analysis. We also pioneered in showing that a TATP molecular ion [TATP + H]+ can be observed with HPLC-MS/MS. The limit of detection for HMTD and TATP was 0.26 and 3.3 ng, respectively, on column by HPLC-MS in the Full Scan mode and 0.08 and 0.8, respectively, by HPLC-APCI-MS/MS in Selected Reaction Monitoring (single mass unit) mode. The method presented has been applied successfully for the identification of peroxides in the bulk solid state (powder sample), as well as in post-blast extracts originating from a forensic case. For the post-blast extracts, the use of tandem MS has been shown clearly to be of crucial importance for the identification and detection of the peroxide explosives.  相似文献   
87.
88.
Within a rational choice framework, secondary data analysis of a survey study on compliance with two Dutch regulatory laws is carried out. Selection of explanatory variables to be considered is guided by a heuristic device, called the Table-of-Eleven. Using adapted logistic regression analysis, we show that self-reported compliance, measured by means of a randomized response procedure, can be explained in terms of benefits of non-compliance, social norms and deterrence, while knowledge and general norm-conformity have no role to play. The impact of various contributing factors turns out to be rather different in size for the two laws.  相似文献   
89.
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   
90.
Law and Critique - The degree of truth of Casanova’s History of My Life is a matter of heated debate. Doubt has been cast particularly on whether his stories of incest with his daughters...  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