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   8116篇
  免费   259篇
各国政治   477篇
工人农民   306篇
世界政治   643篇
外交国际关系   319篇
法律   4425篇
中国共产党   1篇
中国政治   42篇
政治理论   2089篇
综合类   73篇
  2020年   105篇
  2019年   116篇
  2018年   150篇
  2017年   179篇
  2016年   202篇
  2015年   149篇
  2014年   165篇
  2013年   1062篇
  2012年   201篇
  2011年   213篇
  2010年   194篇
  2009年   193篇
  2008年   237篇
  2007年   240篇
  2006年   219篇
  2005年   215篇
  2004年   224篇
  2003年   226篇
  2002年   258篇
  2001年   260篇
  2000年   243篇
  1999年   209篇
  1998年   131篇
  1997年   125篇
  1996年   98篇
  1995年   99篇
  1994年   89篇
  1993年   94篇
  1992年   137篇
  1991年   137篇
  1990年   141篇
  1989年   139篇
  1988年   124篇
  1987年   122篇
  1986年   155篇
  1985年   152篇
  1984年   102篇
  1983年   129篇
  1982年   92篇
  1981年   78篇
  1980年   72篇
  1979年   72篇
  1978年   78篇
  1977年   53篇
  1976年   61篇
  1975年   65篇
  1974年   88篇
  1973年   67篇
  1972年   55篇
  1969年   48篇
排序方式: 共有8375条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
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   
56.
57.
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   
58.
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   
59.
60.
Reviews     
Recently, various authors have examined the relationship between growth in government size and total economic growth. In each case, the authors permitted only a monotonic relationship. This paper examines the issue of a non-linear relationship between growth in government and overall growth in the economy.Government contributes to total economic output in various ways. The provision of Pigovian public goods enhances the productivity of the private sector inputs increasing total output. However, the public decision-making process can result in an inefficient quantity of public goods. The likelihood of this outcome increases with the size of government. Further negative effects are created by the revenue raising and spending mechanisms of government, and the increasing diversion of resources into unproductive rent-seeking activities. The magnitude of these effects is likely to increase with the relative size of government.  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