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   2207篇
  免费   93篇
各国政治   119篇
工人农民   179篇
世界政治   165篇
外交国际关系   115篇
法律   1073篇
中国共产党   11篇
中国政治   75篇
政治理论   527篇
综合类   36篇
  2023年   15篇
  2022年   18篇
  2021年   23篇
  2020年   50篇
  2019年   60篇
  2018年   84篇
  2017年   78篇
  2016年   87篇
  2015年   68篇
  2014年   70篇
  2013年   332篇
  2012年   80篇
  2011年   82篇
  2010年   64篇
  2009年   73篇
  2008年   101篇
  2007年   97篇
  2006年   79篇
  2005年   79篇
  2004年   71篇
  2003年   64篇
  2002年   60篇
  2001年   49篇
  2000年   38篇
  1999年   35篇
  1998年   15篇
  1997年   31篇
  1996年   24篇
  1995年   32篇
  1994年   27篇
  1993年   26篇
  1992年   29篇
  1991年   24篇
  1990年   22篇
  1989年   19篇
  1988年   15篇
  1987年   14篇
  1986年   16篇
  1985年   17篇
  1984年   15篇
  1983年   14篇
  1982年   12篇
  1981年   16篇
  1980年   9篇
  1978年   12篇
  1977年   7篇
  1976年   8篇
  1975年   4篇
  1974年   6篇
  1967年   5篇
排序方式: 共有2300条查询结果,搜索用时 15 毫秒
151.
152.
153.
Asphyxia, not an uncommon cause of sudden death, may result from numerous etiologies. Foreign-body aspiration and strangulation are 2 extrinsic causes. Airway obstruction may also be caused by laryngeal edema, asthma, infection, or anaphylaxis. Chronic causes of asphyxia include musculoskeletal diseases (eg, muscular dystrophy, amyotrophic lateral sclerosis), neurologic disorders (eg, myasthenia gravis, multiple sclerosis), respiratory disease (eg, emphysema, chronic bronchitis), or tumors. The manner of death in cases of asphyxiation may be natural, accidental, homicide, or suicide. For the death investigator, determining the cause and manner of death can often be quite challenging.We report here 2 cases of an esophageal fibrovascular polyp causing sudden asphyxial death, review of the literature, and discussion of other differential diagnoses in the case of asphyxial death.  相似文献   
154.
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   
155.
Health policy experts have recently sounded the warning about the severe health and economic consequences of America's growing rates of obesity. Despite this fact, obesity has only begun to enter America's political consciousness and we have little information about what average Americans think of obesity or whether they support obesity-related policies. Using unique survey data collected by the authors, this essay examines public attitudes toward obesity and obesity policy. We find that, contrary to the views of health experts, most Americans are not seriously concerned with obesity, express relatively low support for obesity-targeted policies, and still view obesity as resulting from individual failure rather than environmental or genetic sources. Given the absence of elite discourse on this problem, we also find that typical determinants of policy preferences, such as ideology or partisanship, are not good predictors of attitudes on obesity policy. Rather, with a low-valence issue such as obesity, the public utilizes other attitudinal frameworks such as their opinions on smoking policy and the environmental culpability for obesity. The implications of these findings for obesity policy and research on health-related public opinion are discussed.  相似文献   
156.
This study was designed to compare the qualitative results and concentrations of methamphetamine (MA) and its metabolite amphetamine (AP) in head hair and hair collected from different parts of the body (axillae and pubis). Hair from subjects (N = 14) suspected MA users was simultaneously collected. Hair preparation involved washing step, fine cutting, overnight extraction, derivatization by the trifluoroacetic anhydride, and gas chromatography/mass spectrometry (GC/MS) using selective ion monitoring. In this study, we found a good correlation of the qualitative results for MA between head hair and hair on other parts of the body, but there were some differences in concentrations of MA and AP. Namely, the concentrations of MA and AP were higher in axillary and pubic hair than in head hair.  相似文献   
157.
Sequence polymorphism of the mitochondrial DNA (mtDNA) control region, hypervariable regions HVR I, HVR II and HVR III, from 51 unrelated China Han (Yan Bian area) were determined by PCR amplification and cycle sequencing.  相似文献   
158.
This study reviewed the public notification policy of sexual offenders against minors in South Korea as compared to community notification programs in the United States. The study then examined the policy's impact on increasing the general public's awareness of such sexual crimes. This is based on the assumption that heightening public awareness can be a starting point in combating such crimes. Results of the data, drawn from a sample of 1,409 Koreans across the nation, showed that the notification policy enhanced public awareness. Factors related to this increase in awareness were people's concern about or familiarity with the policy and people's experience in identifying the existence of known sexual offenders in their communities. Based on the results of this study, strategies for enhancing public awareness of sexual crimes on minors were formulated. The need to develop treatment programs for sexual offenders was likewise highlighted.  相似文献   
159.
The prevalence and age distribution of 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) in hair samples by gas chromatography/mass spectrometry (GC/MS) were studied. The recoveries obtained from hair were 97% and 99% for MDMA and MDA, respectively. The inter- and intra-assay precision and accuracy were determined. Out of 791 hair samples, 44 (5.6 %) contained MDMA and/or MDA. Out of these 44 subjects, urinalyses from 35 were negative for both MDMA and MDA, while only 9 were positive. We also evaluated concentrations of MDMA and MDA, and the metabolite-to-parent drug ratios. This study showed that the abuse of MDMA or MDA was found principally among young adults and male abusers. We found the epidemiology of ecstasy users in Korea between March 2002 and April 2003.  相似文献   
160.
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   
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