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   1371514篇
  免费   101515篇
  国内免费   1842篇
耳鼻咽喉   18066篇
儿科学   44298篇
妇产科学   37433篇
基础医学   204030篇
口腔科学   38727篇
临床医学   124646篇
内科学   274728篇
皮肤病学   30822篇
神经病学   110560篇
特种医学   49217篇
外国民族医学   266篇
外科学   191994篇
综合类   26324篇
现状与发展   3篇
一般理论   602篇
预防医学   115423篇
眼科学   30395篇
药学   100199篇
  6篇
中国医学   2577篇
肿瘤学   74555篇
  2021年   11893篇
  2019年   12747篇
  2018年   17991篇
  2017年   13037篇
  2016年   13743篇
  2015年   15769篇
  2014年   21153篇
  2013年   32156篇
  2012年   45854篇
  2011年   48760篇
  2010年   27462篇
  2009年   25383篇
  2008年   44728篇
  2007年   47780篇
  2006年   46720篇
  2005年   45800篇
  2004年   43461篇
  2003年   41463篇
  2002年   39998篇
  2001年   58747篇
  2000年   60233篇
  1999年   50509篇
  1998年   13807篇
  1997年   12511篇
  1996年   12888篇
  1995年   12113篇
  1994年   11258篇
  1992年   39108篇
  1991年   38432篇
  1990年   37127篇
  1989年   35845篇
  1988年   33163篇
  1987年   32496篇
  1986年   31010篇
  1985年   29171篇
  1984年   22250篇
  1983年   19411篇
  1982年   11476篇
  1979年   21208篇
  1978年   15556篇
  1977年   12950篇
  1976年   12018篇
  1975年   13032篇
  1974年   15823篇
  1973年   15637篇
  1972年   14755篇
  1971年   13813篇
  1970年   13033篇
  1969年   12303篇
  1968年   11461篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
BackgroundThe aim of this paper is to assess the current state of quality and outcomes measures being reported for hepatic resections in the recent literature.MethodsMedline and PubMed databases were searched for English language articles published between 1 January 2002 and 30 April 2013. Two examiners reviewed each article and relevant citations for appropriateness of inclusion, which excluded papers of liver donor hepatic resections, repeat hepatectomies or meta-analyses. Data were extracted and summarized by two examiners for analysis.ResultsFifty-five studies were identified with suitable reporting to assess peri-operative mortality in hepatic resections. In only 35% (19/55) of the studies was the follow-up time explicitly stated, and in 47% (26/55) of studies peri-operative mortality was limited to in-hospital or 30 days. The time period in which complications were captured was not explicitly stated in 19 out of 28 studies. The remaining studies only captured complications within 30 days of the index operation (8/28). There was a paucity of quality literature addressing truly patient-centred outcomes.ConclusionQuality outcomes after a hepatic resection are inconsistently reported in the literature. Quality outcome studies for a hepatectomy should report mortality and morbidity at a minimum of 90 days after surgery.  相似文献   
113.
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   
114.
115.
116.
117.
118.
119.
Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN.  相似文献   
120.
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