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   1336606篇
  免费   94044篇
  国内免费   2910篇
耳鼻咽喉   19721篇
儿科学   40236篇
妇产科学   38664篇
基础医学   187249篇
口腔科学   39825篇
临床医学   112636篇
内科学   262475篇
皮肤病学   30293篇
神经病学   106425篇
特种医学   53679篇
外国民族医学   435篇
外科学   208268篇
综合类   31045篇
现状与发展   6篇
一般理论   436篇
预防医学   92073篇
眼科学   31367篇
药学   100098篇
  4篇
中国医学   2987篇
肿瘤学   75638篇
  2018年   11757篇
  2015年   11898篇
  2014年   16708篇
  2013年   25263篇
  2012年   33029篇
  2011年   34894篇
  2010年   20748篇
  2009年   20240篇
  2008年   33609篇
  2007年   36706篇
  2006年   37287篇
  2005年   36042篇
  2004年   35092篇
  2003年   34077篇
  2002年   33605篇
  2001年   63619篇
  2000年   65332篇
  1999年   55396篇
  1998年   14656篇
  1997年   13461篇
  1996年   12938篇
  1995年   12223篇
  1994年   11473篇
  1992年   42766篇
  1991年   41285篇
  1990年   40555篇
  1989年   39555篇
  1988年   36964篇
  1987年   36409篇
  1986年   34900篇
  1985年   33104篇
  1984年   24822篇
  1983年   21052篇
  1982年   12664篇
  1981年   11568篇
  1980年   10773篇
  1979年   23923篇
  1978年   17068篇
  1977年   14835篇
  1976年   13388篇
  1975年   15267篇
  1974年   18080篇
  1973年   17561篇
  1972年   16810篇
  1971年   15717篇
  1970年   14914篇
  1969年   14347篇
  1968年   13461篇
  1967年   12015篇
  1966年   11260篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
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   
23.
24.
25.
26.
27.
28.
29.
Objectives: The steeling effect suggests that early-life adversity can have a beneficial impact later in life. However, little is known about its underlying mechanisms and long-term outcomes . The study aimed to examine the role of early-life adversity (ELA) on successful aging, and whether this relationship can be explained by mental and physical health.

Method: Socio-demographics, early-life adversity (ELA), individual quality of life (iQoL), and mental and physical health of 270 individuals (Mage = 66.82 years, 71.5% female) were assessed. Polynomial regressions and mediation analyses were conducted.

Results: Significant inverse U-shaped associations were found between ELA and iQoL (β = ?.59, p = .005) and between ELA and mental health (β = ?.64, p = .002), but not between ELA and physical health. Furthermore, mental health significantly mediated the relationship between ELA and iQoL (b = ?.84, BCa CI [?1.66, ?.27]).

Conclusion: Highest level of individual quality of life (i.e. successful aging) was related to a moderate amount of ELA. Additionally, mental health significantly mediated this relationship. These findings suggest that some amount of ELA could be beneficial for successful aging. Resource-focused interventions are needed to improve health and promote successful aging for an underdetected, at-risk subgroup with low early-life adversity.  相似文献   

30.
Doxorubicin (DOX) is the most commonly used anticancer drug; however, it has limited use because prolonged administration may result in severe cardiotoxicity. Simvastatin (SIM), generally prescribed for hypercholesterolaemia, has also shown salubrious results in the monotherapy or combinational drug therapy of different cancers in various models. Nanoparticle drug delivery systems are a novel way of improving therapeutics and also improving the absorption and specificity of drugs towards tumour cells. In this study, we exploited this technology to increase drug specificity and minimize imminent adverse effects. In this study, the antitumour activity of the combination formulas of DOX and SIM, either loaded in water (DOX‐SIM‐Solution) or nanoemulsions (NEs) (DOX‐SIM‐NE), was evaluated in a Swiss albino mouse model of Ehrlich ascites carcinoma. The anticancer effect was assessed by quantifying the change in body weight, mean survival time, and percent increase in lifespan (%ILS), determining haematological and serum biochemical parameters (liver function test, kidney function test and lipid profile parameters) as well as studying the histopathological alterations in liver tissues. We observed a clear increase in %ILS of the DOX‐SIM‐Solution group (265.30) that was double the %ILS of the DOX‐SIM‐NE group (134.70). However, DOX‐SIM‐NE had a non‐toxic effect on the haematological parameters, whereas DOX‐SIM‐Solution increased the levels of haemoglobin and lymphocytes. Furthermore, the encapsulation of SIM and DOX into NEs improved the levels of all serum biochemical parameters compared to the DOX‐SIM‐Solution. A reduction in the side effects of DOX‐SIM‐NE on the liver was also established using light microscopy, which revealed that the morphologies of the hepatocytes of the mice were less affected by administration of the DOX‐SIM‐NE treatment than with the DOX‐SIM‐Solution treatment. The study showed that incorporating SIM into the DOX‐loaded‐NE formulation remarkably improved its efficiency and simultaneously reduced its adverse effects.  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