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   431篇
  免费   16篇
各国政治   27篇
工人农民   64篇
世界政治   32篇
外交国际关系   33篇
法律   176篇
中国政治   8篇
政治理论   101篇
综合类   6篇
  2023年   3篇
  2022年   2篇
  2021年   3篇
  2020年   6篇
  2019年   8篇
  2018年   18篇
  2017年   21篇
  2016年   17篇
  2015年   13篇
  2014年   11篇
  2013年   69篇
  2012年   11篇
  2011年   11篇
  2010年   12篇
  2009年   9篇
  2008年   10篇
  2007年   22篇
  2006年   20篇
  2005年   10篇
  2004年   8篇
  2003年   11篇
  2002年   17篇
  2001年   9篇
  2000年   7篇
  1999年   3篇
  1998年   8篇
  1997年   4篇
  1996年   6篇
  1995年   10篇
  1994年   4篇
  1993年   3篇
  1992年   6篇
  1991年   5篇
  1990年   2篇
  1989年   7篇
  1988年   7篇
  1987年   2篇
  1986年   3篇
  1985年   3篇
  1984年   2篇
  1983年   3篇
  1982年   6篇
  1981年   7篇
  1980年   2篇
  1978年   2篇
  1977年   3篇
  1976年   2篇
  1975年   5篇
  1974年   6篇
  1967年   2篇
排序方式: 共有447条查询结果,搜索用时 15 毫秒
91.
This paper investigates the impact of extending free school lunch to all students, regardless of income, on academic performance in New York City middle schools. Using a difference-in-differences design and unique longitudinal, student-level data, we derive credibly causal estimates of the impacts of “Universal Free Meals” (UFM) on test scores in English Language Arts (ELA) and mathematics, and participation in school lunch. We find UFM increases academic performance by as much as 0.083 standard deviations in math and 0.059 in ELA for non-poor students, with smaller, statistically significant effects of 0.032 and 0.027 standard deviations in math and ELA for poor students. Further, UFM increases participation in school lunch by roughly 11.0 percentage points for non-poor students and 5.4 percentage points for poor students. We then investigate the academic effects of school lunch participation per se, using UFM as an instrumental variable. Results indicate that increases in school lunch participation improve academic performance for both poor and non-poor students; an additional lunch every two weeks increases test scores by roughly 0.08 standard deviations in math and 0.07 standard deviations in ELA. Finally, we explore potential unintended consequences for student weight outcomes, finding no evidence that UFM increases the probability that students are obese or overweight. We also find no evidence of increases in average body mass index (BMI). Instead, we find some evidence that participation in school lunch improves weight outcomes for non-poor students. Results are robust to an array of alternative specifications and assumptions about the sample.  相似文献   
92.
93.
ABSTRACT

Police personnel are likely to be affected by stress and compassion fatigue, which may have important consequences for health, well-being and job performance. There are certain individual differences which may protect against compassion fatigue, for example mental toughness, personality and self-care behaviours. However, there is little research examining all of these constructs in combination with policing. The current study aimed to gather information regarding the prevalence of compassion fatigue, compassion satisfaction and perceived stress within a large UK police force, and their relationships with personality, mental toughness and self-care activities. A questionnaire was completed by 605 police employees within a UK police force. The results demonstrated that 20% of personnel suffered from negative psychological outcomes and that these outcomes were predicted by individual differences and self-care activities. The requirement for shift work, and mental toughness scores, significantly predicted compassion satisfaction, compassion fatigue and perceived stress. The analyses also revealed a role for gender, tenure, personality and self-care in several aspects of well-being. The implications of these findings are discussed, considering the current contexts in which policing operates, with the aim of improving the psychological well-being of police officers and staff.  相似文献   
94.
95.
96.
97.
98.
99.
100.
This article traces the history of a 16-year court battle over the child welfare system in Kansas City, Missouri, which eventually headed toward resolution as the result of an innovative public policy negotiation process. The process combined the substantive expertise of nationally and locally respected child welfare professionals with political muscle at the state, local, and community levels to develop and implement a plan for reform. If the results of this process become institutionalized in the Kansas City child welfare system, it will represent a significant transformation in the governing culture and practices of the system and the community it serves.  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