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   14529篇
  免费   258篇
各国政治   657篇
工人农民   1262篇
世界政治   837篇
外交国际关系   722篇
法律   7263篇
中国政治   64篇
政治理论   3908篇
综合类   74篇
  2023年   43篇
  2022年   28篇
  2021年   59篇
  2020年   109篇
  2019年   162篇
  2018年   1406篇
  2017年   1368篇
  2016年   1187篇
  2015年   180篇
  2014年   197篇
  2013年   1126篇
  2012年   352篇
  2011年   1080篇
  2010年   1158篇
  2009年   738篇
  2008年   890篇
  2007年   899篇
  2006年   213篇
  2005年   299篇
  2004年   406篇
  2003年   356篇
  2002年   260篇
  2001年   134篇
  2000年   135篇
  1999年   108篇
  1998年   106篇
  1997年   113篇
  1996年   117篇
  1995年   127篇
  1994年   124篇
  1993年   89篇
  1992年   84篇
  1991年   94篇
  1990年   66篇
  1989年   69篇
  1988年   69篇
  1987年   67篇
  1986年   78篇
  1985年   70篇
  1984年   71篇
  1983年   72篇
  1982年   59篇
  1981年   60篇
  1980年   39篇
  1979年   51篇
  1978年   43篇
  1977年   46篇
  1976年   34篇
  1974年   17篇
  1967年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Risk adjustment (RA) consists of a series of techniques that account for the health status of patients when predicting or explaining costs of health care for defined populations or for evaluating retrospectively the performance of providers who care for them. Although the federal government seems to have settled on an approach to RA for Medicare Advantage programs, adoption and implementation of RA techniques elsewhere have proceeded much more slowly than was anticipated. This article examines factors affecting the adoption and use of RA outside the Medicare program using case studies in six U.S. health care markets (Baltimore, Seattle, Denver, Cleveland, Phoenix, and Atlanta) as of 2001. We found that for purchasing decisions, RA was used exclusively by public agencies. In the private sector, use of risk adjustment was uncommon and scattered and assumed informal and unexpected forms. The most common private sector use of RA was by health plans, which occasionally employed RA in negotiations with purchasers or to allocate resources internally among providers. The article uses classic technology diffusion theory to explain the adoption and use of RA in these six markets and derives lessons for health policy generally and for the future of RA in particular. For health policy generally, the differing experiences of public and private actors with RA serve as markers of the divergent paths that public and private health care sectors are pursuing with respect to managed care and risk sharing. For the future of RA in particular, its history suggests the need for health service researchers to consider barriers to use adoption and new analytic technologies as they develop them.  相似文献   
992.
Carbon monoxide (CO) poisoning as a cause of death is well documented in industrialized countries. The objective of this study was to compare demographic data in deaths due to accidents (in fires) and suicides in the same population between 1988 and 1998. Furthermore, the potential effect of a community wide education effort regarding safety in the home was assessed. Postmortem reports were reviewed for all deaths examined at the Office of the Cuyahoga County Coroner in Cleveland, OH, USA. During the study period, there were 209 accidental deaths due to fires in the home (6.5% of all accidents in the home) and 182 CO deaths by suicide (9.8% of all suicides). Demographic characteristics of the two groups differed: while males represented the majority of cases in both groups (55% of accidents, 70% suicides), race specific death rates were higher for whites than blacks (18/100,000 white, 3/100,000 black) in suicides compared with 29/100,000 deaths for blacks and 11/100,000 for whites in accidental cases. Fire deaths were prevalent in the young (0-9 years) and old (>60) whereas in the suicide group the age specific death rate was highest for those over 70 years. The majority of fire deaths occurred in the city of Cleveland but suicides were prevalent in the suburbs. More fire deaths occurred in December than any other month whereas more suicides occurred in April. In 1992, there was a community wide effort to provide free smoke detectors to residents in Cleveland. In 1992, there were 4.2/100,000 fire deaths in the city. This decreased to 0.6/100,000 in 1996, increased to 1.2/100,000 in 1997 followed by a decrease to 0.8/100,000 in 1998. This suggested that the program may have aided in decreasing these types of deaths. Deaths due to fires in the suburbs were <1/100,000 throughout the study period.  相似文献   
993.
A new retrieval system for a 3D facial image database was designed and its reliability was experimentally examined. This system has two steps, firstly to automatically adjust the orientation of all 3D facial images in a database to that of the 2D facial image of a target person, and then to identify the facial image of the target person from the adjusted 3D facial images in the database using a graph-matching method. From the experimental study [M. Yoshino, K. Imaizumi, T. Tanijiri, J.G. Clement, Automatic adjustment of facial orientation in 3D face image database, Jpn. J. Sci. Tech. Iden. 8 (2003) 41-47], it is concluded that the software developed for the first step will be applicable to the automatic adjustment of facial orientation in the 3D facial image database. In 28 out of 110 sets (25.5%), the 3D image of the target person was chosen as the best match (from a database of 132 3D facial images) according to the similarity of the facial image characteristics based on the graph matching. The 3D facial image of the target person was ranked in the top of 10 of the database in 75 out of 110 sets (68.2%). These results suggest that this system is inadequate for the identification level, but may be feasible for screening method in a small database. It will be necessary to further pursue the possibility of realization of a facial image retrieval system for a large database such as suspects' facial images in future.  相似文献   
994.
Prevention science has produced information about risk and protective factors that predict adolescent drug use and related problem behaviors. This paper investigates the Communities That Care Youth Survey that measures multiple risk and protective factors. Using a sample of 172,628 students who participated in surveys administered in seven states in 1998, analyses were conducted to test the factor structure of these risk and protective factors and to test the equivalence of the factor models across five racial/ethnic groups (African Americans, Asians or Pacific Islanders, Caucasians, Hispanic Americans, and Native Americans), four grade levels (6th, 8th, 10th, and 12th) and both gender groups. Results support the construct validity of the surveys risk and protective factor scales and indicate that the measures are equally reliable across males and females and five racial/ethnic groups. Implications of these findings for science-based prevention planning are discussed.  相似文献   
995.
A large literature points to the abominable condition of American jails. Comparison of national surveys of jail conditions conducted in 1972 and 1978 indicates that what little improvement has occurred is minimal compared to remaining problems. A number of factors have prevented state-set standards from achieving widespread improvement in local jail conditions: high costs, local autonomy and lack of credible threats for forcing compliance. The failure of New York State to implement adequate health standards illustrates the limitations of the standards approach. Other approaches, such as strategies for replacing local jails with regional facilities, deserve the attention of policy researchers.  相似文献   
996.
A generalized revision of Albert Cohen's theory of negativistic delinquency is presented. The antecedent conditions of that theory have been broadened to include all contradictions between ideals and the practices that might, but do not, carry them out. Anger produced by distributive injustice has replaced reaction-formation as a causal mechanism. As revised, the theory appears to explain a wider range of “ornery” activities, some of which were negative cases for the original Cohen theory.  相似文献   
997.
998.
The relationship of police patrol-car staffing to response time is examined. The first systematic study of police patrol-car staffing, conducted in San Diego in 1977, found that two one-officer cars responded to the scene of an incident faster than one two-officer car. Given the study design, this finding was puzzling. When two one-officer cars are dispatched, at least one of the cars has farther to go, and the extra travel distance should require extra travel time. The present study replicated the previous empirical analysis with data from the Kansas City Response Time Analysis Study. Although it was expected that additional control variables would provide an explanation for the findings, the results were the same. Two one-officer cars are faster than one two-officer car. One explanation for this finding is that peer pressure among officers provides different incentives for rapid response in one- and two-officer cars. The policy implication is that the deployment of two-officer cars cannot be justified by minimized response time.  相似文献   
999.
1000.
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