全文获取类型
收费全文 | 912篇 |
免费 | 90篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 48篇 |
妇产科学 | 15篇 |
基础医学 | 158篇 |
口腔科学 | 60篇 |
临床医学 | 103篇 |
内科学 | 171篇 |
皮肤病学 | 15篇 |
神经病学 | 59篇 |
特种医学 | 79篇 |
外科学 | 79篇 |
综合类 | 27篇 |
预防医学 | 105篇 |
眼科学 | 4篇 |
药学 | 58篇 |
中国医学 | 1篇 |
肿瘤学 | 36篇 |
出版年
2023年 | 8篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 15篇 |
2018年 | 16篇 |
2017年 | 11篇 |
2016年 | 8篇 |
2015年 | 15篇 |
2014年 | 22篇 |
2013年 | 39篇 |
2012年 | 46篇 |
2011年 | 40篇 |
2010年 | 29篇 |
2009年 | 26篇 |
2008年 | 32篇 |
2007年 | 58篇 |
2006年 | 29篇 |
2005年 | 35篇 |
2004年 | 35篇 |
2003年 | 28篇 |
2002年 | 25篇 |
2001年 | 38篇 |
2000年 | 23篇 |
1999年 | 23篇 |
1998年 | 21篇 |
1997年 | 22篇 |
1996年 | 30篇 |
1995年 | 13篇 |
1994年 | 23篇 |
1993年 | 13篇 |
1992年 | 16篇 |
1991年 | 17篇 |
1990年 | 20篇 |
1989年 | 25篇 |
1988年 | 16篇 |
1987年 | 15篇 |
1986年 | 24篇 |
1985年 | 17篇 |
1984年 | 13篇 |
1983年 | 14篇 |
1982年 | 13篇 |
1981年 | 13篇 |
1980年 | 12篇 |
1979年 | 5篇 |
1977年 | 12篇 |
1975年 | 10篇 |
1974年 | 5篇 |
1973年 | 7篇 |
1971年 | 4篇 |
1970年 | 5篇 |
排序方式: 共有1020条查询结果,搜索用时 375 毫秒
1.
2.
3.
Ticks of the Ornithodoros moubata complex were collected from domestic pig sties and dwelling houses, and from a warthog habitat, and tested for the presence of African swine fever (ASF) virus. Collections were made in 9 of the 24 districts of Malawi, these being primarily the districts in which O. moubata is most numerous. ASF virus was isolated from ticks collected in both domestic pig sties and houses in certain villages in Mchinji district where ASF outbreaks had recently occurred. Mchinji district is in the centre of a large ASF enzootic area which stretches into other districts of Malawi and also into Zambia and Mozambique. The high titre of virus in some of the ticks demonstrates that O. moubata can act as a virus reservoir and potential vector of disease in the field situation in Malawi. 相似文献
4.
5.
6.
7.
Simon Mellor 《British medical journal》2003,327(7410):330
8.
Promoting clinically effective practice: general practitioners' awareness of sources of research evidence 总被引:3,自引:1,他引:2
Prescott K; Lloyd M; Douglas HR; Haines A; Humphrey C; Rosenthal J; Watt I 《Family practice》1997,14(4):320-323
BACKGROUND: Practitioners are being encouraged to base their clinical
practice on research evidence. In order to do this, they must be aware of
and use the sources of evidence. METHODS: A questionnaire survey was
undertaken to establish GPs' awareness of research evidence in their
clinical practice and, in fundholding practices, its influence on
purchasing plans. Questionnaires were sent to 360 lead fundholders in North
Thames Region and 440 of a random sample of the remaining general
practitioners in the region for comparison. RESULTS: Questionnaires were
returned by 62% of lead fundholders and 63% of GPs in the random sample.
There was limited use of the electronic sources of clinical effectiveness.
There was greater reported awareness of published sources of research
evidence and fundholding GPs were significantly more likely to have
referred to publications summarizing research evidence. CONCLUSIONS: GPs
seem to make more use of published clinical effectiveness sources than the
electronic databases. Consequently, they need educational and technical
support if they are to make full use of the available sources of research
evidence available in other media.
相似文献
9.
On the Importance of Age-Adjustment Methods in Ecological Studies of Social Determinants of Mortality 总被引:1,自引:0,他引:1
Objective. To illustrate the potential sensitivity of ecological associations between mortality and certain socioeconomic factors to different methods of age-adjustment.
Data Sources. Secondary analysis employing state-level data from several publicly available sources. Crude and age-adjusted mortality rates for 1990 are obtained from the U.S. Centers for Disease Control. The Gini coefficient for family income and percent of persons below the federal poverty line are from the U.S. Bureau of Labor Statistics. Putnam's (2000) Social Capital Index was downloaded from http://www.bowlingalone.com ; the Social Mistrust Index was calculated from responses to the General Social Survey, following the method described in Kawachi et al. (1997) . All other covariates are obtained from the U.S. Census Bureau.
Study Design. We use least squares regression to estimate the effect of several state-level socioeconomic factors on mortality rates. We examine whether these statistical associations are sensitive to the use of alternative methods of accounting for the different age composition of state populations. Following several previous studies, we present results for the case when only mortality rates are age-adjusted. We contrast these results with those obtained from regressions of crude mortality on age variables.
Principal Findings. Different age-adjustment methods can cause a change in the sign or statistical significance of the association between mortality and various socioeconomic factors. When age variables are included as regressors, we find no significant association between mortality and either income inequality, minority racial concentration, or social capital.
Conclusions. Ecological associations between certain socioeconomic factors and mortality may be extremely sensitive to different age-adjustment methods. 相似文献
Data Sources. Secondary analysis employing state-level data from several publicly available sources. Crude and age-adjusted mortality rates for 1990 are obtained from the U.S. Centers for Disease Control. The Gini coefficient for family income and percent of persons below the federal poverty line are from the U.S. Bureau of Labor Statistics. Putnam's (2000) Social Capital Index was downloaded from http://www.bowlingalone.com ; the Social Mistrust Index was calculated from responses to the General Social Survey, following the method described in Kawachi et al. (1997) . All other covariates are obtained from the U.S. Census Bureau.
Study Design. We use least squares regression to estimate the effect of several state-level socioeconomic factors on mortality rates. We examine whether these statistical associations are sensitive to the use of alternative methods of accounting for the different age composition of state populations. Following several previous studies, we present results for the case when only mortality rates are age-adjusted. We contrast these results with those obtained from regressions of crude mortality on age variables.
Principal Findings. Different age-adjustment methods can cause a change in the sign or statistical significance of the association between mortality and various socioeconomic factors. When age variables are included as regressors, we find no significant association between mortality and either income inequality, minority racial concentration, or social capital.
Conclusions. Ecological associations between certain socioeconomic factors and mortality may be extremely sensitive to different age-adjustment methods. 相似文献
10.
Chris Evans Janice Connell Michael Barkham Chris Marshall John Mellor‐Clark 《Clinical psychology & psychotherapy》2003,10(6):374-388
There are a number of problems for evidence‐based practice (EBP) including limited generalizability of efficacy research results, the consequent lack of confidence in the relevance of such research, and the conceptual distance of most practitioners from the research process. The result is that EBP, although sound in principle, often fails to achieve its aim of improving practice. Practice‐based evidence (PBE) provides a complementary bridge for the gap between research and practice to offset some of these problems, promoting collaboration between mental health services and academic institutions. This paper presents the initial results of such a collaboration via three phases: (1) the development of a referential database for primary care counselling services, (2) ‘practitioner‐friendly’ feedback on grouped data to services, and (3) the combination of the two to build an evidence base for work with ethnic minorities—an area in which research trials are not well adapted to provide much evidence. Copyright © 2003 John Wily & Sons, Ltd. 相似文献