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   8322篇
  免费   286篇
各国政治   605篇
工人农民   265篇
世界政治   642篇
外交国际关系   322篇
法律   4866篇
中国共产党   8篇
中国政治   43篇
政治理论   1804篇
综合类   53篇
  2021年   50篇
  2020年   127篇
  2019年   147篇
  2018年   239篇
  2017年   249篇
  2016年   281篇
  2015年   237篇
  2014年   184篇
  2013年   1002篇
  2012年   248篇
  2011年   229篇
  2010年   229篇
  2009年   231篇
  2008年   297篇
  2007年   341篇
  2006年   322篇
  2005年   247篇
  2004年   257篇
  2003年   215篇
  2002年   220篇
  2001年   246篇
  2000年   253篇
  1999年   174篇
  1998年   100篇
  1997年   87篇
  1996年   73篇
  1995年   80篇
  1994年   79篇
  1993年   62篇
  1992年   112篇
  1991年   113篇
  1990年   135篇
  1989年   107篇
  1988年   107篇
  1987年   109篇
  1986年   126篇
  1985年   132篇
  1984年   88篇
  1983年   96篇
  1982年   73篇
  1981年   71篇
  1980年   49篇
  1979年   67篇
  1978年   70篇
  1975年   53篇
  1974年   67篇
  1973年   60篇
  1972年   48篇
  1970年   43篇
  1969年   48篇
排序方式: 共有8608条查询结果,搜索用时 15 毫秒
61.
Quadratic pieces of fleece measuring 16 mm2 were soaked with 10 different blood-samples in the dilution steps of 1:1, 1:10, 1:100, 1:1000, respectively, and were tested in blood group typing and identification tests of forensic serology. The above spezified dilutions correspond with 5 microliters, 0.5 microliter, 0.05 microliter and 0.005 microliter of blood, respectively. The detection limit of the microspectrometric test for blood was the dilution 1:10, of the porphyrine test a dilution above 1:100, whereas the preliminary test for blood (peroxidase) succeeded always up to a dilution of 1:1000 and the species determination by the radial immunodiffusion test in agar gels succeeded in most cases op to a dilution of 1:1000. The detection limit of the anti-human globulin inhibition test was between the dilution steps 1:10 and 1:100 when non-titrated and undiluted anti-human globulin serum was used. Gc- and ABO-grouping were possible up to a dilution of 1:100 and were thus the most sensitive grouping systems. Phenotyping of the enzyme-systems and the Gm/Km-system usually required stains with considerably higher blood concentrations i.e. stains of undiluted blood.  相似文献   
62.
Telecommunications regulation has experienced a fundamentalshift from rate regulation to increased reliance on compelledaccess, perhaps best exemplified by the Telecommunications Actof 1996's imposition of no fewer than four new access requirements.Unfortunately, each access requirement is governed by a separateset of rules for determining both the scope and the price ofaccess. The resulting ad hoc regime has created difficult definitionalproblems and opportunities for regulatory arbitrage. In thisarticle we propose a system inspired by the discipline of mathematicsknown as graph theory that integrates all of the different formsof access into a single analytical framework. This system separatesdifferent access regimes into five categories: (1) retail access,(2) wholesale access, (3) interconnection access, (4) platformaccess, and (5) unbundled access. It also provides insightsinto how each type of access complicates the already difficultproblems of network configuration and management and introducesinefficient biases into decisions about network capacity anddesign. The approach we propose also provides insights intothe transaction cost implications of the different types ofaccess. Drawing on the Coasean theory of the firm, our approachexamines the tradeoffs between internal governance costs andthe external transaction costs of providing access to offera theory of network boundaries. This framework shows how accessregulation distorts networks' natural boundaries and providesa basis for evaluating whether private ordering through marketswould lead to more efficient network design.  相似文献   
63.
Eighteen external quality assessment (proficiency testing) samples were prepared from client specimens collected with the Intercept® oral fluid collection device and by spiking drug-free oral fluid. Samples were circulated in pairs at quarterly intervals to 13 UK and USA based laboratories for analysis by a panel of OraSure micro-plate Intercept® enzyme immunoassay kits and hyphenated mass spectrophotometric techniques. During the survey, there was a single case of non-specificity in a false report for methadone. The major errors were of lack of sensitivity relative to the concentration thresholds specified for the immunoassays. The sensitivity for overall ‘present’/‘not found’ reports calculated as true positives/(true positives + false negatives) were for the amfetamine specific assay 50%, methyl-amfetamines 93%, barbiturates 64%, cannabinoids 73%, cocaine and metabolites 100%, benzodiazepines 69%, methadone 95%, opiates 79% (opiates excluding oxycodone 93%), phencyclidine 93% and human gamma-globulin 97%. A small number of the sensitivity errors were attributable to errors in chromatographic confirmation techniques.  相似文献   
64.
65.
Book reviews     
Turkey in the Middle East By Philip Robins. Pinter for the Royal Institute of international Affairs. 1991.130 pp. £22.50. ISBNO 86187 198 7. PBk £8.95. ISBN 0 86187 1995.

Hitler Slept Late and other blunders that cost him the war By James P. Duffy. London: Praeger. 1991.176pp. £17.50.

Alliance within the alliance: Franco‐German Military Cooperation and the European Pillar of Defense By David G. Haglund. Boulder: Westview Press, 1991. 213 pp.

Homeward Bound? Allied Forces in the New Germany Edited by David G. Haglund and Olaf Mager. Boulder: Westview Press, 1992. 299 pp. £24.95

Avoiding War: Problems of crisis management By Alexander L. George (ed.), Westview Press, 1991. 590 pp. £16.95.

The Future of NATO: Facing an Unreliable Enemy in an Uncertain Environment By S.N. Drew et al. Praeger Publishers, New York, 1991. pp. 206.

Parliament and international relations Edited by Charles Carstairs and Richard Ware. Milton Keynes: Open University Press, 1991. 195 pp. £12.99 (paperback)  相似文献   

66.
Book Review     
Radical myths and superpower relations in the 1980s

A review of Mark Kaldor, Gerard Holden, and Richard Falk (eds), The New Detente: Rethinking East‐West Relations, Verso, London, 1989.

Paul Taylor and A.J.R. Groom, Global Issues in the United Nations Framework, Basingstoke, Hampshire, The MacMillan Press Ltd., 1989.

Roger A. Coate, Unilateralism, Ideology, and US Foreign Policy: The United States in and out of UNESCO, Lynne Reinner Publishers, London, 1988.

Bary Buzan, Morten Kelstnip, Pierre Lemaitre, Elzbieta Tromer, and Ole Weaver, The European Security Order Recast: Scenarios for the Post‐Cold War Era, Pinter Publishers, London & New York, 1990, pp.x. 282, £8.95 pbk, £30 hbk.  相似文献   

67.
68.
A definitive explanation of "crib" or "cot" death remains unknown. An unusual incidental autopsy finding of agenesis of the corpus callosum in a case presenting as "near miss" sudden infant death syndrome (SIDS) is discussed. Hitherto, only a single case associated with SIDS has been reported in the literature. The condition may be easily missed outside the interest in neuropathology.  相似文献   
69.
70.
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