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   8616篇
  免费   28篇
各国政治   236篇
工人农民   1090篇
世界政治   216篇
外交国际关系   312篇
法律   4814篇
中国政治   1篇
政治理论   1968篇
综合类   7篇
  2023年   2篇
  2022年   3篇
  2021年   5篇
  2020年   7篇
  2019年   12篇
  2018年   1280篇
  2017年   1211篇
  2016年   1026篇
  2015年   82篇
  2014年   29篇
  2013年   92篇
  2012年   194篇
  2011年   937篇
  2010年   1021篇
  2009年   600篇
  2008年   752篇
  2007年   707篇
  2006年   24篇
  2005年   78篇
  2004年   177篇
  2003年   149篇
  2002年   39篇
  2001年   8篇
  2000年   12篇
  1999年   4篇
  1998年   13篇
  1997年   19篇
  1996年   21篇
  1995年   29篇
  1994年   23篇
  1993年   2篇
  1992年   7篇
  1991年   2篇
  1990年   3篇
  1989年   3篇
  1988年   2篇
  1986年   2篇
  1985年   3篇
  1984年   10篇
  1983年   10篇
  1982年   7篇
  1981年   2篇
  1979年   7篇
  1978年   8篇
  1977年   13篇
  1975年   1篇
  1973年   1篇
  1971年   1篇
  1968年   1篇
  1966年   1篇
排序方式: 共有8644条查询结果,搜索用时 15 毫秒
111.
112.
113.
114.
115.
Successful drug intervention policies rely on timely assessment of size of drug users and close monitoring of trend regarding drug abuse. Taking advantage of data collected by the Central Registration System for Drug Abusers of Macau (CRSDAM), this study applied open population capture-recapture models with data augmentation techniques to estimate the size of drug users and to identify influential factors on capture and survival probabilities from 2009 to 2014. In particular, the data augmentation technique was used to address missing data issues. The estimated size of drug users has been slowly declining from 2442 (95% Bayesian credible interval [BCI] 2042–2914) in 2009 to 807 (95% BCI 654–1000) in 2014 with a small fluctuation of 2251 (95% BIC 1950–2599) in 2011, and the estimated cumulative size of drug users is 6199 (95% BCI 5651–6873), which is correspondent to a prevalence rate of 1.20% of the current population aged 15 to 54. Although the estimated sizes of total, narcotic, and other drug users were declining, the size of stimulant users might be increasing. People who used narcotics as their first drug and who were reported by governmental agencies were more likely to stay in the registration system, while those who used needle injection were less likely to stay. Governmental agencies, higher education, and using needle injection were negatively associated with the probability of capture over time, while using narcotics as the first drug was positively associated with it.  相似文献   
116.
117.
118.
119.
120.
US State governments invest in early-stage innovative activity as an economic development strategy. Nevertheless, attention directed at the public sector’s role in this capacity has been placed on federal policy actions overlooking the growing role of states. The primary aims of this paper are two-fold: (1) to articulate the motivations for multilevel public support for small business innovative activity, placing emphasis on state level incentives directed towards entrepreneurial activity; and (2) to empirically evaluate the State Match Phase I (SMP-I) program. The SMP-I program is a diffuse state level policy designed to complement the federal Small Business Innovation Research (SBIR) program by offering noncompetitive matching funds to the state’s successful SBIR Phase I recipients. This offers an opportunity to examine the marginal impact of public R&D given the state intervention. This paper employs a state and year fixed effects model and considers two outcome variables—SBIR Phase II success rates and SBIR Phase I application activity. To account for industrial heterogeneity, the data are stratified by the federal mission agencies. Results from the empirical analysis indicate that the state match increases the Phase II success rates for firms participating in the National Science Foundation SBIR program.  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