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   77233篇
  免费   3293篇
各国政治   4536篇
工人农民   3092篇
世界政治   6522篇
外交国际关系   3913篇
法律   39338篇
中国共产党   14篇
中国政治   790篇
政治理论   21359篇
综合类   962篇
  2021年   423篇
  2020年   1183篇
  2019年   1542篇
  2018年   1775篇
  2017年   2103篇
  2016年   2260篇
  2015年   1837篇
  2014年   2108篇
  2013年   10652篇
  2012年   1855篇
  2011年   2038篇
  2010年   1976篇
  2009年   2163篇
  2008年   2036篇
  2007年   2022篇
  2006年   2114篇
  2005年   2014篇
  2004年   1915篇
  2003年   1738篇
  2002年   1740篇
  2001年   2099篇
  2000年   1861篇
  1999年   1577篇
  1998年   1251篇
  1997年   1087篇
  1996年   1054篇
  1995年   1018篇
  1994年   1042篇
  1993年   1033篇
  1992年   1206篇
  1991年   1273篇
  1990年   1185篇
  1989年   1237篇
  1988年   1207篇
  1987年   1221篇
  1986年   1246篇
  1985年   1278篇
  1984年   1134篇
  1983年   1194篇
  1982年   990篇
  1981年   938篇
  1980年   751篇
  1979年   841篇
  1978年   655篇
  1977年   612篇
  1976年   561篇
  1975年   488篇
  1974年   500篇
  1973年   506篇
  1972年   439篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
801.
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   
802.
This article surveys the voluminous economic literature on commoditybundling. While bundling has been widely studied, the vast majorityof the literature has focused on theoretical treatments of bundlingthat demonstrate a wide range of reasons why firms might engagein bundling. These papers generally contain restrictive assumptions,including assumptions regarding the existence of monopoly insome markets, and the nature of rivalry in others. The modelscontained in these papers also generally suppress the more obviousand ubiquitous reasons firms may use bundling. Moreover, thesemodels have not been subject to robustness checks, nor havetheir assumptions been tested empirically. This review of theeconomic literature generally confirms the US Solicitor General'sview in 3M v. LePage's regarding the underdeveloped state ofthe economics literature and its position that the US SupremeCourt should defer promulgation of antitrust standards for bundling.While the literature has demonstrated the possibility that bundlingcan generate anticompetitive harm, it does not provide a reliableway to gauge whether the potential for harm would outweigh anydemonstrable benefits from the practice. As a result, the widespreadapplication of the antitrust laws to bundling by firms can generatesignificant error costs by erroneously condemning or deterringefficient business practices. In the future, economists shouldseek to expand their understanding of both the anticompetitiveand procompetitive reasons firms engage in bundling. This willentail studying the reasons why bundling is adopted by firmswithout market power, relaxing the assumption of monopoly intheoretical models, and generating testable hypotheses and thedata to test them.  相似文献   
803.
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   
804.
805.
806.
Two conditions must be met in order for a person to be rightly considered the victim of a crime. First, there must be the victim of some form of harm. Second, the harm in question was the direct result of an act in which the harmed individual did not knowingly consent to take part. What are the dynamics of consent and how important should consent be in defining and placing criminal responsibility in crimes where women are sexually victimized? Finally, how does the conceptualization of victimization change when viewed from liberal and radical feminist perspectives?  相似文献   
807.
808.
809.
810.
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