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   434篇
  免费   23篇
各国政治   33篇
工人农民   48篇
世界政治   24篇
外交国际关系   32篇
法律   193篇
中国政治   3篇
政治理论   118篇
综合类   6篇
  2023年   2篇
  2021年   5篇
  2020年   8篇
  2019年   6篇
  2018年   16篇
  2017年   18篇
  2016年   15篇
  2015年   12篇
  2014年   9篇
  2013年   75篇
  2012年   9篇
  2011年   7篇
  2010年   10篇
  2009年   15篇
  2008年   13篇
  2007年   17篇
  2006年   16篇
  2005年   11篇
  2004年   13篇
  2003年   10篇
  2002年   9篇
  2001年   10篇
  2000年   10篇
  1999年   10篇
  1998年   9篇
  1997年   6篇
  1996年   7篇
  1995年   8篇
  1994年   6篇
  1993年   4篇
  1992年   5篇
  1991年   6篇
  1990年   5篇
  1989年   5篇
  1988年   4篇
  1987年   9篇
  1986年   5篇
  1985年   3篇
  1984年   7篇
  1983年   6篇
  1982年   2篇
  1981年   5篇
  1980年   2篇
  1979年   5篇
  1977年   2篇
  1973年   2篇
  1971年   2篇
  1969年   2篇
  1968年   6篇
  1966年   3篇
排序方式: 共有457条查询结果,搜索用时 15 毫秒
101.
In the long history of monopolies, business method patents area novel and recent edition. In the Digital Age, where time ismoney and speed is everything, innovative methods for undertakingbusiness are as important to a business as the products or servicesit provides to its clients. In recent years several reviews,conducted in both Australia and internationally,4 have questionedthe appropriateness of patenting business methods. This paperreviews the availability of business method patents in Australiain light of the 2006 decision of the Full Court of the FederalCourt in Grant v Commissioner of Patents,5 which confirmed theneed in Australia for a ‘useful product’ to issuefrom the working of a method (business or otherwise) in orderfor the method to be patentable. This paper will review argumentsboth criticising and defending business method patents and considerwhether business methods warrant special treatment.  相似文献   
102.
103.
104.
105.
106.
107.
108.
This paper articulates a citation‐based approach to science policy evaluation and employs that approach to investigate the impact of the United States’ 2001 policy regarding the federal funding of human embryonic stem cell (hESC) research. We evaluate the impact of the policy on the level of U.S. hESC research, the U.S. position at the knowledge frontier, and the strategic response of U.S. scientists. Consistent with recent research on the science of science and innovation policy, we employ a difference‐in‐differences approach using bibliometric data with the aim of analyzing the causal impact of the policy on cumulative research. Our estimates suggest that in the aftermath of the 2001 policy, U.S. production of hESC research lagged 35 to 40 percent behind anticipated levels. However, this relative decline was largely concentrated in the years 2001 to 2003 and ameliorated over time. The rebound in U.S. hESC research after 2003 was driven by contributions by researchers at elite U.S. institutions and U.S. researchers who collaborated with international partners. The results suggest that scientists respond strategically to research funding restrictions and that modest science policy shifts can have a significant influence on the within‐country composition of research and the pattern of global research collaboration.  相似文献   
109.
This study examines the psychometric properties of the Childhood Trauma Questionnaire short form (CTQ-SF) with street youth who have run away or been expelled from their homes (N = 397). Internal reliability coefficients for the five clinical scales ranged from .65 to .95. Confirmatory Factor Analysis (CFA) was used to test the five-factor structure of the scales yielding acceptable fit for the total sample. Additional multigroup analyses were performed to consider items by gender. Results provided only evidence of weak factorial invariance. Constrained models showed invariance in configuration, factor loadings, and factor covariances but failed for equality of intercepts. Mean trauma scores for street youth tended to fall in the moderate to severe range on all abuse/neglect clinical scales. Females reported higher levels of abuse and neglect. Prevalence of child maltreatment of individual forms was very high with 98% of street youth reporting one or more forms; 27.4% of males and 48.9% of females reported all five forms. Results of this study support the viability of the CTQ-SF for screening maltreatment in a highly vulnerable street population. Caution is recommended when comparing prevalence estimates for male and female street youth given the failure of the strong factorial multigroup model.  相似文献   
110.
This article reports on a systematic review of English language, peer-reviewed publications from 13 empirical studies with donor-conceived children and adults regarding their experiences and perceptions of donor conception. A total of 19 articles that met the inclusion criteria were reviewed. These were identified by means of a bibliographic search of four electronic databases for the period 1990-2011 and supplemented by the authors' personal knowledge of work in this field. No reports from such studies appeared prior to 2000, and more than half have been published since 2008, demonstrating the relative novelty of research in this field. Much of the reviewed research evidence concerns individuals conceived through sperm donation conducted under a regime promoting both anonymity and nondisclosure. Consequently, there is little research that pertains to individuals conceived through other forms of collaborative reproduction, nor to those conceived under arrangements and regimes in which early parental disclosure is both advocated and practised and the identity of the donor and of other genetic relatives may be accessible to donor-conceived individuals. The studies consistently report that most donor-conceived people have an interest in securing information about their genetic and biographical heritage - more information than most of them have been able to obtain. Although a number of methodological limitations in the research base are identified, the authors conclude that the evidence is sufficiently robust to promote the implementation of policies and practices that promote transparency and openness in collaborative reproduction, thus reflecting the importance of maximising future choices and opportunities for donor-conceived people.  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