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   1457415篇
  免费   107024篇
  国内免费   4530篇
耳鼻咽喉   18430篇
儿科学   46920篇
妇产科学   39362篇
基础医学   215971篇
口腔科学   40408篇
临床医学   136851篇
内科学   284871篇
皮肤病学   29861篇
神经病学   122147篇
特种医学   51224篇
外国民族医学   367篇
外科学   197681篇
综合类   29372篇
现状与发展   1篇
一般理论   482篇
预防医学   129246篇
眼科学   32440篇
药学   108752篇
  6篇
中国医学   3673篇
肿瘤学   80904篇
  2021年   12950篇
  2019年   13934篇
  2018年   20145篇
  2017年   14697篇
  2016年   15665篇
  2015年   17874篇
  2014年   23865篇
  2013年   36641篇
  2012年   52185篇
  2011年   55256篇
  2010年   31250篇
  2009年   27985篇
  2008年   49494篇
  2007年   52353篇
  2006年   52132篇
  2005年   50204篇
  2004年   47571篇
  2003年   45097篇
  2002年   43633篇
  2001年   63953篇
  2000年   65954篇
  1999年   54957篇
  1998年   15109篇
  1997年   13617篇
  1996年   13451篇
  1995年   12762篇
  1994年   11871篇
  1993年   11120篇
  1992年   43111篇
  1991年   42113篇
  1990年   40819篇
  1989年   38557篇
  1988年   35733篇
  1987年   34806篇
  1986年   33239篇
  1985年   31644篇
  1984年   23782篇
  1983年   20233篇
  1982年   12070篇
  1979年   21715篇
  1978年   15419篇
  1977年   12660篇
  1976年   12451篇
  1975年   12783篇
  1974年   15682篇
  1973年   15367篇
  1972年   14238篇
  1971年   13251篇
  1970年   12264篇
  1969年   11250篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
123.
124.
125.
There are an estimated 56 million orphans and vulnerable children across sub-Saharan Africa. Communities typically care for orphan children through informal caring arrangements – either within or outside of kinship networks. Within Kenya, an estimated 250,000 children live on the streets. There is less research related to fostering attitudes of this special population than orphans and vulnerable children generally. Important research over the past decade has illuminated multiple ways in which children are made more vulnerable because of HIV, including parental death and street-migration from HIV-affected households. As HIV transitions from a terminal illness to a chronic, manageable one, research is also required to establish how parents living with HIV can be an asset to children. In this study, we assess whether mothers living with HIV were very willing to foster biologically-related children, and street-involved children, how these fostering attitudes differed from mothers not living with HIV, and whether differences in fostering attitudes by reported HIV status were mediated by social support, family functioning and general self-rated health. Approximately 40% of mothers living with HIV were very willing to provide long-term foster care to biologically-related or street-involved children. This was less than the percentage of mothers not living with HIV, who were very willing to foster biologically-related children (61%) or street-involved children (58%). Significant portions of these differences were explained by social support, family functioning and general self-rated health. Multi-sectoral approaches are suggested by these findings in order to improve the child-fostering capacity of mothers living with HIV. Improving social support, family functioning and general self-rated health among HIV-infected mothers may not only provide protective benefits for the mothers and their children, but also expand the community’s capacity to care for orphan and vulnerable children.  相似文献   
126.
127.
Alterations in autophagy are increasingly being recognized in the pathogenesis of proteinopathies like Alzheimer's disease (AD). This study was conducted to evaluate whether melatonin treatment could provide beneficial effects in an Alzheimer model related to tauopathy by improving the autophagic flux and, thereby, prevent cognitive decline. The injection of AAV‐hTauP301L viral vectors and treatment/injection with okadaic acid were used to achieve mouse and human ex vivo, and in vivo tau‐related models. Melatonin (10 μmol/L) impeded oxidative stress, tau hyperphosphorylation, and cell death by restoring autophagy flux in the ex vivo models. In the in vivo studies, intracerebroventricular injection of AAV‐hTauP301L increased oxidative stress, neuroinflammation, and tau hyperphosphorylation in the hippocampus 7 days after the injection, without inducing cognitive impairment; however, when animals were maintained for 28 days, cognitive decline was apparent. Interestingly, late melatonin treatment (10 mg/kg), starting once the alterations mentioned above were established (from day 7 to day 28), reduced oxidative stress, neuroinflammation, tau hyperphosphorylation, and caspase‐3 activation; these observations correlated with restoration of the autophagy flux and memory improvement. This study highlights the importance of autophagic dysregulation in tauopathy and how administration of pharmacological doses of melatonin, once tauopathy is initiated, can restore the autophagy flux, reduce proteinopathy, and prevent cognitive decline. We therefore propose exogenous melatonin supplementation or the development of melatonin derivatives to improve autophagy flux for the treatment of proteinopathies like AD.  相似文献   
128.
129.
130.
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