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   25509篇
  免费   1360篇
各国政治   1067篇
工人农民   1125篇
世界政治   1860篇
外交国际关系   804篇
法律   16976篇
中国共产党   2篇
中国政治   152篇
政治理论   4756篇
综合类   127篇
  2021年   146篇
  2020年   502篇
  2019年   560篇
  2018年   709篇
  2017年   751篇
  2016年   841篇
  2015年   645篇
  2014年   690篇
  2013年   2576篇
  2012年   644篇
  2011年   748篇
  2010年   703篇
  2009年   744篇
  2008年   729篇
  2007年   704篇
  2006年   729篇
  2005年   638篇
  2004年   631篇
  2003年   533篇
  2002年   600篇
  2001年   1005篇
  2000年   922篇
  1999年   699篇
  1998年   391篇
  1997年   307篇
  1996年   299篇
  1995年   289篇
  1994年   298篇
  1993年   294篇
  1992年   465篇
  1991年   478篇
  1990年   461篇
  1989年   454篇
  1988年   467篇
  1987年   420篇
  1986年   490篇
  1985年   476篇
  1984年   379篇
  1983年   358篇
  1982年   268篇
  1981年   258篇
  1980年   214篇
  1979年   322篇
  1978年   180篇
  1977年   159篇
  1976年   136篇
  1975年   130篇
  1974年   185篇
  1973年   139篇
  1972年   130篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Kindergarten policy varies widely both across and within states. Over the past decade, a number of states have instituted a full‐day kindergarten requirement and others are considering it as a way to increase educational achievement. Many parents also support full‐day kindergarten as a source of child care. This paper uses the Early Child Longitudinal Study–Kindergarten Class of 1998–1999 to evaluate the efficacy of this policy. In ordinary least squares, probit, county fixed effects, and instrumental variables models, we find that there are initial benefits for students and the mothers of students who attend full‐day kindergarten, but that these differences largely evaporate by third grade. Contrary to claims by some advocates, attending full‐day kindergarten is found to have no additional benefit for students in families with income below the poverty threshold. © 2006 by the Association for Public Policy Analysis and Management  相似文献   
42.
The study presents a method for the demonstration of esophageal varices at autopsy by gastroesophageal phlebography. The veins visible on the radiographs were controlled and evaluated by studying the gross appearance of sections of the esophagus at the level of the varicose veins and by histologic examination of the sections. The phlebography was found to be useful in estimating the varicose and normal veins of the esophagus. The study indicates further that the degree of varicosity is not always proportional to the severity of cirrhosis of the liver, and there may be varicose esophageal veins in patients with liver or heart disorders without hepatic cirrhosis.  相似文献   
43.
This study examined the nature of police response to domestic violence incidents with a focus on the identification of areas of police intervention that female victims of domestic abuse find “most” helpful and “least” helpful. The first part of the study was based on the analysis of a random sample of incident reports of domestic abuse cases recorded in 2000 and 2001. These reports were examined to obtain information about the characteristics of domestic abuse victims and summary information about the incidents of domestic abuse offenses. The second stage of the research study involved a telephone survey conducted with a random sample of fifty female domestic abuse victims who called the police. The study examined female victims' perceptions of how the police responded to the domestic abuse incidents, how helpful or not so helpful victims found the police to be when they responded to their calls, and how their cases were handled by the legal system.  相似文献   
44.
The purpose of this study was to examine the relationship between job demands, job resources, and burnout, and to examine if burnout could predict both work and health-related outcomes among police officers. The participants were 223 Norwegian police officers, and data were collected using a questionnaire. The study was part of a national survey of both health care and non-health care professions. The overall level of burnout was low among police officers compared to other occupational groups tested in Norway. Both job demands and job resources were related to burnout, especially work-family pressure was an important predictor for all of the three burnout dimensions. Burnout predicted individual outcomes, such as psychosomatic complaints and satisfaction with life, as well as work outcomes, such as job satisfaction, intention to quit, and organizational commitment. Suggestions for potential interventions to reduce burnout and negative individual and organizational consequences are presented.  相似文献   
45.
Family courts and child welfare agencies across the country are charged with protecting the safety of our children. That mission has become more challenging with increasing federal legislation and decreasing funding. In Buffalo, N.Y., the Family Court and the Department of Social Services have teamed up to respond to this challenge. With minimal additional staffing and resources, they have led a collaboration of agencies and service providers to change the way business is done in child welfare. By engaging each other in an interagency system change effort, the amount of time children spend in foster care has been reduced. The collaboration has been able to accomplish in a relatively short time what no agency had previously been able to accomplish on its own. The beneficiaries have been the children and families of Erie County.  相似文献   
46.
In the wake of the 1990 amendments to the Clean Air Act, localities across the United States initiated public information campaigns both to raise awareness of threats to air quality and to change behavior related to air pollution by recommending specific behavioral changes in the campaign messages. These campaigns are designed to reduce the health hazards associated with poor air quality and to avoid federal sanctions resulting from the failure to meet air quality standards. As in many other communities across the country, a coalition of government agencies and businesses initiated a public information campaign in the Atlanta metropolitan region to reduce certain targeted behaviors, mainly driving. A two‐stage model used to analyze data from a rolling sample survey shows that the centerpiece of the information campaign—air quality alerts—was effective in raising awareness and reducing driving in a segment of the population. When the overall information campaign was moderated by employers' participation in programs to improve air quality, drivers significantly reduced the number of miles they drove and the number of trips they took by car on days when air quality alerts were sounded. Public information campaigns can be successful in increasing awareness, but changing well‐established behaviors, such as driving, is likely to require institutional mediation to provide social contexts that support the behavioral change, as well. © 2003 by the Association for Public Policy Analysis and Management.  相似文献   
47.
Report of an unusual finding of bones on the shore of the Baltic Sea. Although the morphological findings appeared similar to a human foot skeleton, a quick identification as sea dog bone was possible.  相似文献   
48.
In many countries it is left to the discretion of the court to accept or reject conclusions based on sampling procedures as applied to the total drug exhibit. As an alternative to this subjective approach, a statistical basis is presented using binomial and hypergeometric distributions to determine a lower limit for the proportion of units in a population which contains a drug, at a given confidence level. A method for calculating the total weight of a drug present in a population within a given confidence interval is also presented. In the event of no failures (all units sampled contain a drug), a sample size of six or seven units is generally sufficient to state that a proportion of at least 0.70 of the population contains a drug at a confidence level of at least 90%. When failures do occur in the sample, point estimation is used as the basis for selecting the appropriate sample size.  相似文献   
49.
A case of the sudden death of a 14-month-old girl due to massive hemorrhage in a primitive neuroectodermal tumor (PNET) is presented along with a review of the relevant literature. PNET is a rare, malignant brain neoplasm occurring predominantly in children.  相似文献   
50.
We report a case of rapid death from thrombotic thrombocytopaenic purpura (TTP) in a young pregnant lady who developed full blown symptoms soon after caesarean section. Extensive intramyocardial confluent haemorrhages and widespread microthrombi in heart, brain, adrenals and kidney were found at autopsy. Thrombotic thrombocytopaenic purpura is an uncommon condition, which carries a high fatality rate if untreated. Awareness of this syndrome together with its high risk of sudden death underlines the importance of rapid diagnosis and treatment.  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