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   3069篇
  免费   369篇
  国内免费   5篇
耳鼻咽喉   26篇
儿科学   122篇
妇产科学   60篇
基础医学   412篇
口腔科学   98篇
临床医学   424篇
内科学   544篇
皮肤病学   48篇
神经病学   280篇
特种医学   127篇
外科学   317篇
综合类   141篇
一般理论   1篇
预防医学   342篇
眼科学   75篇
药学   235篇
中国医学   2篇
肿瘤学   189篇
  2022年   39篇
  2021年   103篇
  2020年   53篇
  2019年   76篇
  2018年   89篇
  2017年   57篇
  2016年   53篇
  2015年   50篇
  2014年   72篇
  2013年   109篇
  2012年   157篇
  2011年   117篇
  2010年   76篇
  2009年   66篇
  2008年   130篇
  2007年   141篇
  2006年   109篇
  2005年   126篇
  2004年   109篇
  2003年   107篇
  2002年   103篇
  2001年   92篇
  2000年   95篇
  1999年   91篇
  1998年   33篇
  1997年   26篇
  1996年   40篇
  1995年   35篇
  1994年   30篇
  1993年   32篇
  1992年   57篇
  1991年   62篇
  1990年   66篇
  1989年   56篇
  1988年   59篇
  1987年   42篇
  1986年   50篇
  1985年   37篇
  1984年   44篇
  1983年   31篇
  1980年   25篇
  1979年   36篇
  1978年   27篇
  1972年   24篇
  1971年   37篇
  1970年   29篇
  1969年   31篇
  1968年   22篇
  1967年   28篇
  1966年   31篇
排序方式: 共有3443条查询结果,搜索用时 15 毫秒
991.
992.
CONTEXT: While there has been considerable research on prenatal alcohol use, there have been limited studies focused on women in rural and small-town environments. PURPOSE: This 2-part study examines gender differences in attitudes and perceived barriers to intervention in large community sample of persons living in rural and small-town environments in Kentucky (n = 3,346). The study also examines rural/small-town prenatal service providers' perceptions of barriers to assessment and intervention with pregnant substance abusers (n = 138). METHODS: Surveys were administered to a convenience sample of employees and customers from 16 rural and small-town community outlets. There were 1503 males (45%) and 1843 females (55%) ranging in age from under 18 years old to over 66 years old. Surveys also were mailed to prenatal providers in county health departments of the 13-county study area, with 138 of 149 responding. FINDINGS: Overall results of the community sample suggest that neither males nor females were knowledgeable about the harmful effects of alcohol use during pregnancy. Results also indicate substantial gender differences in alcohol attitudes, knowledge, and perceived barriers. Further, prenatal care providers identified several barriers in assessment and treatment of pregnant women with alcohol use problems in rural and small-town communities, including lack of knowledge and comfort with assessment as well as a lack of available and accessible treatment for referrals.  相似文献   
993.
Positron emission tomography (PET), in combination with (11)C-raclopride, was used to examine the effects of phencyclidine (PCP) on dopamine (DA) in the primate striatum. In addition, we explored the hypotheses that GABAergic pathways as well as molecular targets beyond the N-methyl-D-aspartate (NMDA) receptor complex (ie dopamine transporter proteins, DAT) contribute to PCP's effects. In the first series of experiments, (11)C-raclopride was administered at baseline and 30 min following intravenous PCP administration. In the second series of studies, gamma-vinyl GABA (GVG) was used to assess whether enhanced GABAergic tone altered NMDA antagonist-induced changes in DA. Animals received an initial PET scan followed by pretreatment with GVG (300 mg/kg), then PCP 30 min prior to a second scan. Finally, we explored the possible contributions of DAT blockade to PCP-induced increases in DA. By examining (11)C-cocaine binding a paradigm in which PCP was coadministered with the radiotracer, we assessed the direct competition between these two compounds for the DAT. At 0.1, 0.5, and 1.0 mg/kg, PCP decreased (11)C-raclopride binding by 2.1, 14.9+/-2.2 and 8.18+/-1.1%, respectively. These effects were completely attenuated by GVG (3.38+/-3.1% decrease in (11)C-raclopride binding). Finally, PCP (0.5 mg/kg) decreased (11)C-cocaine binding by 25.5+/-4.3%, while at 1.0 mg/kg this decrease was 13.5%, consistent with a competitive interaction at the DAT. These results suggest that PCP may be exerting some direct effects through the DAT and that GABA partially modulates NMDA-antagonist-induced increases in striatal DA.  相似文献   
994.
995.
The aim of the systematic review was to determine the effect of cisapride compared with placebo or other non-surgical therapies for the treatment of symptoms of gastro-oesophageal reflux in children. We searched MEDLINE, EMBASE, the Cochrane Controlled Trials Register, Science Citation Index and reference lists for randomized controlled trials which compared cisapride with placebo or other non-surgical therapy in children. We included only trials which reported reflux-related symptoms as an outcome, provided that cisapride was administered orally for at least I week. Seven trials (286 children in total) compared cisapride with placebo. Two trials reported good concealment of treatment allocation. The pooled odds ratio for the 'same or worse' symptoms was 0.34 (95% CI 0.10, 1.19). There was substantial heterogeneity between studies (P < 0.00001) and the funnel plot was asymmetrical. Adverse effects (mainly diarrhoea) were not significantly increased with cisapride (pooled odds ratio (OR) 1.80: 0.87, 3.70). The reflux index was significantly reduced in children treated with cisapride (weighted mean difference -6.49: -10.13, -2.85). One study (50 children) compared cisapride with gaviscon plus carobel: the OR for the 'same or worse' symptoms was 3.26 (0.93, 11.38). There was no clear evidence that cisapride reduced symptoms of gastro-oesophageal reflux. As smaller, poorer quality studies were biased in favour of a positive treatment effect, the pooled OR overestimated the potential benefits of cisapride. There was some evidence to suggest that gaviscon plus carobel may be a more effective option than cisapride.  相似文献   
996.
997.
998.
This study examined sun protection in families with adolescents from an action-theoretical perspective. Interview data were collected from 20 families about their attitudes and behaviors around sunbathing and sun protection. The data support the understanding of project as joint goal-directed action over time as the basis on which these behaviors are organized in families. Families used the language of goal-directed action to discuss family sun protection. Differences between families with focused and diffuse sun-protection projects are identified. Sun protection in families as one part of an array of family goal-directed actions and projects has implications for health promotion.  相似文献   
999.
Primary nocturnal enuresis (PNE), or bed-wetting, is a distressing urinary condition which can persist through childhood and beyond. Altered prostaglandin and nitric oxide production have been observed in children with PNE, and prostaglandin inhibitors are known to be of therapeutic value. Omega-3 fatty acids have the potential to influence the symptoms of PNE by inhibition of prostaglandin and renal nitric oxide production. In addition, children with PNE have an inappropriate startle response and an apparent maturational delay of the central nervous system. Research clearly shows that omega-3 fatty acids play a critical role in the development and function of the central nervous system. It is our contention that inadequate omega-3 intake may play a role in the lack of inhibitory input to the startle and micturition centers in PNE.  相似文献   
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