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   22848篇
  免费   2304篇
  国内免费   768篇
耳鼻咽喉   170篇
儿科学   296篇
妇产科学   207篇
基础医学   923篇
口腔科学   550篇
临床医学   3747篇
内科学   1719篇
皮肤病学   161篇
神经病学   796篇
特种医学   584篇
外国民族医学   7篇
外科学   1367篇
综合类   3367篇
现状与发展   1篇
一般理论   1篇
预防医学   5748篇
眼科学   107篇
药学   3359篇
  80篇
中国医学   2136篇
肿瘤学   594篇
  2024年   179篇
  2023年   591篇
  2022年   975篇
  2021年   1138篇
  2020年   1205篇
  2019年   942篇
  2018年   879篇
  2017年   925篇
  2016年   995篇
  2015年   947篇
  2014年   1754篇
  2013年   1912篇
  2012年   1580篇
  2011年   1618篇
  2010年   1243篇
  2009年   1157篇
  2008年   1079篇
  2007年   1032篇
  2006年   908篇
  2005年   713篇
  2004年   618篇
  2003年   523篇
  2002年   403篇
  2001年   363篇
  2000年   302篇
  1999年   296篇
  1998年   238篇
  1997年   183篇
  1996年   169篇
  1995年   134篇
  1994年   138篇
  1993年   101篇
  1992年   104篇
  1991年   84篇
  1990年   68篇
  1989年   58篇
  1988年   55篇
  1987年   37篇
  1986年   45篇
  1985年   49篇
  1984年   42篇
  1983年   18篇
  1982年   20篇
  1981年   20篇
  1980年   27篇
  1979年   9篇
  1978年   16篇
  1977年   11篇
  1976年   4篇
  1975年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
医院综合效益评价中的权数(三)——估计权数   总被引:2,自引:0,他引:2  
在医院综合效益评价中,估计权数由评价专家根据经验对评价指标的重要程度的一种评估,这类数据通常用的AHP法进行处理。本文用AHP的递推算法计算估计权数,这种算法不仅计算简单,而且易达到一致性的要求,其估计的剩余误差小于AHP法。  相似文献   
62.
Worksite health promotion programs have become increasinglyprevalent in the United States, and one or more health promotionprograms are found in two-thirds of all private worksites with50 or more employees. Reasons for recent growth in program frequencyinclude increased concern for worker health, rapidly escalatingemployer payments for health care benefits to workers, and growingevidence of a strong linkage between employee health and productivity.Published results of evaluations to date suggest that worksitehealth promotion programs can have positive impacts on healthbehaviors and health status. In addition, economic analysesare suggesting that some programs can affect the slope of healthcare costs and have the potential of high cost-effectivenesscompared to some clinical interventions. A number of researchchallenges remain, particularly understanding the influencesof the worksite environment and how employee health promotionprograms affect individual and organizational productivity.  相似文献   
63.
There are many occupational stress management programmes availablewhich are designed to prevent and cure the negative aspectsof job-stress. The focus of the programmes can be directed towardsthe individual worker, the working group, the organization ofthe work or the organization as a whole. Moreover, programmesshow a considerable variation with respect to the type of interventionsthey promote and their underlying assumptions, as well as theirduration and costs. In this paper, effect studies of occupationalstress programmes published between 1987 and 1994 are reviewed.The aim is to give a practical overview of the variety in occupationalstress programmes, their scope, applicability and the evidenceof their effectiveness. The paper updates the review by DeFrankand Cooper published in 1989.  相似文献   
64.
Using switching detection and variational equations for the shooting method   总被引:1,自引:0,他引:1  
We study in this paper the resolution by single shooting of an optimal control problem with a bang‐bang control involving a large number of commutations. We focus on the handling of these commutations regarding the precise computation of the shooting function and its Jacobian. We first observe the impact of a switching detection algorithm on the shooting method results. Then, we study the computation of the Jacobian of the shooting function, by comparing classical finite differences to a formulation using the variational equations. We consider as an application a low thrust orbital transfer with payload maximization. This kind of problem presents a discontinuous optimal control, and involves up to 1800 commutations for the lowest thrust. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
65.
The paper describes output measures of performance of the WesternAustralian Health Promotion Foundation (Healthway), using asystem known as graduated project evaluation (GPE). Resultsare reported at the basic and process levels of evaluation on588 health and sponsorship projects, and at the impact levelbased on surveys of 5710 spectators and participants at 53 sport,arts and racing events sponsored by Healthway funds. At thebasic and process levels the average Healthway project reached7449 people directly and generated media coverage of healthmessages on 27.3 occasions. It secured, on average, 0.99 healthystructural reforms in recreational or cultural venues, involvedthe participation of local community members in project administrationin 38% of instances, and provided 1596 person-hours of healtheducation. Non-smoking, safe drinking, nutrition, exercise,sun protection, safe sex and injury prevention health messageswere promoted using 24 different types of sponsor benefits.Of the 5710 respondents surveyed post-event, 67% were awareof the promoted health message and 82% of these understood whatthe message meant. Four per cent of all respondents intendedto take action ranging from seeking information to adoptingthe health behaviour. A comparison of the cost-effectivenessof small and large sponsorship projects is given to illustratethe use of GPE to inform funding decisions. Smaller projectsoutperformed larger projects on all available indicators. Wediscuss the peculiar features of the health promotion foundationconcept, methods to improve its performance and implicationsfor future research.  相似文献   
66.
The assessment of economic and quality-of-life outcomes of health care interventions is moving into a new era, with such assessments increasingly being made within the context of controlled clinical trials. Traditionally the measurement of many variables in economic evaluations, particularly costs, has been deterministic. In the context of clinical trials the measurement of variables is stochastic, with the standard principles of statistical inference being applied to analyse differences between treatments in terms of effectiveness. Economists participating in clinical research are therefore being called upon to specify the sample size for the economic component of the evaluation and to undertake statistical tests for differences in cost or cost-effectiveness. This paper discusses the current methodological issues surrounding stochastic measurement in clinical trials, discusses the additional issues raised by the assessment of economic and quality-of-life outcomes and specifies the challenges facing economists if they are to answer the questions now being posed about economic analysis by statisticians and clinical researchers. It is concluded that application of the standard principles of statistical inference to economic data is not straightforward and will require value judgements to be made about statistical significance and economic importance, which may differ from those already made in purely clinical studies.  相似文献   
67.
Previous studies of cerebral structure in substance abusers yielded controversial results, largely due to issues of subject selection and/or limitations of experimental techniques. The purpose of the present study was to assess whether the ventricle-to-brain ratio (VBR), determined volumetrically by magnetic resonance imaging (MRI), differed in polysubstance abusers (n = 10), as compared with age-matched controls (n = 10). Subjects were male volunteers 21–39 years of age. The values of VBR in the polydrug abuse group were not larger than those in control group, nor was there any tendency toward relative ventriculomegaly in the substance abusers. Therefore, the present findings provide no evidence that polysubstance abuse produces abnormalities of gross brain structure in relatively young and physically healthy men.  相似文献   
68.
This introduction traces the increasing awareness of the prevalence of child sexual abuse over the last 20 years, examines the nature and consequences of such abuse and summarizes current information on the use of group treatment and its evaluation with sexually abused children and adolescents and their parents. Four examples of group treatment with different populations of abused children are described in this issue.  相似文献   
69.
Conventional treatments have not slowed down the ever expanding low back pain (LBP) problem. Traditional treatment has most probably contributed to the growth of the problem. Therefore, in a search for new solutions, 'functional restoration' has been devised. In connection with chronic LBP the term has been associated with a full-day program lasting from 3 to 5 weeks. it includes multidisciplinary treatment of patients in groups with intensive physical and ergonomic training, psychological pain management, back school, as well as teaching in social/work related issues. The key concepts are 'acceptance of the pain', 'activity', 'self-responsibility', 'multidisciplinary' and 'quantitative functional evaluation (QFE)'. The latter is aimed so that the participants can feel the physical improvement, encouraging them to be able to go back to work, or at least to lead a more active life style. Several controlled studies suggest a lasting effect in terms of regaining their ability to work and improving pain behavior for a good part of disabled chronic LBP patients. However, it is noteworthy that randomized studies seemingly show poorer results than studies not employing randomized controls.  相似文献   
70.
The Italian mental health reform nine years on   总被引:2,自引:0,他引:2  
It is 9 years since the mental health reform was passed by the Italian Parliament. The author presents a data-based evaluation of the effects of the Italian mental health reform. There are still many problems to be resolved: More than 30,000 inpatients are still in psychiatric hospitals and little is known of the fate of those discharged in recent years. District mental health services are still lacking, especially in the south of the country; Psychiatric units in the general hospital function much the same way as the "old" psychiatric hospitals. The pattern of mental health services consumers have changed: They are younger with less severe psychiatric diagnosis and come from a higher social background.  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