首页 | 官方网站   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   158394篇
  免费   10025篇
  国内免费   1209篇
医药卫生   169628篇
  2023年   1067篇
  2022年   3057篇
  2021年   5012篇
  2020年   2474篇
  2019年   3522篇
  2018年   4326篇
  2017年   3485篇
  2016年   4539篇
  2015年   6197篇
  2014年   7388篇
  2013年   8759篇
  2012年   13105篇
  2011年   12528篇
  2010年   7212篇
  2009年   6220篇
  2008年   8940篇
  2007年   8697篇
  2006年   7872篇
  2005年   7366篇
  2004年   6491篇
  2003年   5696篇
  2002年   5005篇
  2001年   3941篇
  2000年   3660篇
  1999年   2880篇
  1998年   1211篇
  1997年   961篇
  1996年   767篇
  1995年   715篇
  1994年   602篇
  1993年   574篇
  1992年   1328篇
  1991年   1300篇
  1990年   1156篇
  1989年   1126篇
  1988年   1032篇
  1987年   1032篇
  1986年   817篇
  1985年   857篇
  1984年   648篇
  1983年   515篇
  1982年   371篇
  1981年   381篇
  1980年   322篇
  1979年   520篇
  1978年   417篇
  1977年   298篇
  1976年   289篇
  1974年   335篇
  1973年   336篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
To assess the relationship between the DSM-III criteria for attention deficit disorder with hyperactivity (ADDH) and the DSM-III-R criteria for attention-deficit hyperactivity disorder (ADHD), children from an inner city parochial school were evaluated using a 30-item teacher questionnaire consisting of the DMS-III and DSM-III-R criteria for these disorders, the revised Conners Parent and Teacher Questionnaires, and a continuous performance test. Diagnostic groups were established based on teacher ratings of the DSM items and evaluated in relation to the rating scale data and continuous performance test. While children who were identified by teachers as having ADDH almost always satisfied the criteria for ADHD, a new group of children who were hyperactive and impulsive but less clearly inattentive also met the criteria for ADHD. Implications of the change in diagnostic criteria are discussed.  相似文献   
42.
43.
The atypical antipsychotic risperidone is often prescribed to pediatric patients with neuropsychiatric disorders, though its effects on the developing brain remain unclear. Accordingly, we studied the effects of repeated treatment of risperidone on dopamine receptors in brain regions of juvenile rat. Levels of dopamine receptors (D(1), D(2), D(3), D(4)) in forebrain regions of juvenile rats were quantified after 3 weeks of treatment with three different doses of risperidone (0.3, 1.0 and 3.0 mg/kg) and compared findings to those in adult rats treated with risperidone (3.0 mg/kg/day) previously. Risperidone (at 1.0 and 3.0 mg/kg/day) increased levels of D(1) receptors in nucleus accumbens and caudate-putamen of juvenile, but not adult rats. Conversely, all three doses of risperidone dose-dependently increased D(2) labeling in medial prefrontal cortex and hippocampus, and D(4) receptor in nucleus accumbens, caudate-putamen and hippocampus of juvenile animals as well as in adults. Only the high dose of risperidone (3.0 mg/kg) increased D(2) receptors in caudate-putamen in both juvenile and adult brain. D(3) receptors were not altered by risperidone in any brain region at any dose or age. The findings indicate dose-dependent effects of risperidone on dopamine receptors in developing animals, and that juvenile animals are more sensitive than adults to the cerebral effects of risperidone.  相似文献   
44.
45.
46.
47.
48.
Diseases like rotavirus afflict both upper- and lower-income countries, but most serious illnesses and deaths occur among the latter. It is a vital public health issue that vaccines for these types of global diseases can recover research and development (R&D) costs from high-priced markets quickly so that manufacturers can offer affordable prices to lower-income nations. Cost recovery depends on how high R&D costs are, and this study attempts to replace high, unverified estimates with lower, more verifiable estimates for two new vaccines, RotaTeq (Merck) and Rotarix (GlaxoSmithKline or GSK), based on detailed searches of public information and follow-up interviews with senior informants. We also offer a new perspective on “cost of capital” as a claim for recovery from public bodies. Our estimates suggest that companies can recover all fixed costs quickly from affluent markets and thus can offer these vaccines to lower-income countries at prices they can afford. Better vaccines are a shared project between companies and public health agencies; greater transparency and consistency in reporting of R&D costs is needed so that fair prices can be established.  相似文献   
49.
50.
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-23

京公网安备 11010802026262号