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   736891篇
  免费   33916篇
  国内免费   971篇
耳鼻咽喉   9679篇
儿科学   24556篇
妇产科学   18518篇
基础医学   121622篇
口腔科学   18208篇
临床医学   64074篇
内科学   132641篇
皮肤病学   16742篇
神经病学   49355篇
特种医学   30854篇
外国民族医学   150篇
外科学   108481篇
综合类   8802篇
现状与发展   2篇
一般理论   115篇
预防医学   54273篇
眼科学   16298篇
药学   56209篇
  3篇
中国医学   1320篇
肿瘤学   39876篇
  2018年   9613篇
  2017年   8278篇
  2016年   8577篇
  2015年   10682篇
  2014年   11987篇
  2013年   14801篇
  2012年   26379篇
  2011年   23383篇
  2010年   13000篇
  2009年   13355篇
  2008年   19128篇
  2007年   21481篇
  2006年   21275篇
  2005年   28393篇
  2004年   29436篇
  2003年   24712篇
  2002年   19610篇
  2001年   27521篇
  2000年   25799篇
  1999年   25120篇
  1998年   6278篇
  1997年   5040篇
  1996年   5080篇
  1995年   4778篇
  1992年   20790篇
  1991年   22181篇
  1990年   22444篇
  1989年   21828篇
  1988年   20036篇
  1987年   19717篇
  1986年   18465篇
  1985年   17405篇
  1984年   12662篇
  1983年   10678篇
  1982年   5242篇
  1981年   4683篇
  1979年   12484篇
  1978年   8583篇
  1977年   6849篇
  1976年   6929篇
  1975年   8807篇
  1974年   10141篇
  1973年   9599篇
  1972年   9076篇
  1971年   8759篇
  1970年   8169篇
  1969年   7680篇
  1968年   7175篇
  1967年   6557篇
  1966年   5653篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
35.
36.
37.
38.
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   
39.
40.
Attachment is a behavioral and physiological system, which enables individual’s dynamic adaptation to its environment. Attachment develops in close interaction between an infant and his/her mother, plays an important role in the development of the infant’s brain, and influences the quality of interpersonal relationships throughout life.Security of attachment is believed to influence individual response to stress, exposing insecurely organized individuals to deregulated autonomic nervous system and exaggerated hypothalamic-pituitary-adrenal activity, which, in turn, produces increased and prolonged exposure to stress-hormones. Such stress responses may have considerable implications for the development of diverse health-risk conditions, such as insulin resistance and hyperlipidemia, shown by numerous studies.Although the mechanisms are not yet fully understood, there is compelling evidence highlighting the role of psychological stress in the development of type 1 diabetes (T1D). One of the possible contributing factors for the development of T1D may be the influence of attachment security on individual stress reactivity. Thus, the suggestion is that insecurely attached individuals are more prone to experience increased and prolonged influence of stress hormones and other mechanisms causing pancreatic beta-cell destruction.The present paper opens with a short overview of the field of attachment in children, the principal attachment classifications and their historic development, describes the influence of attachment security on individual stress-reactivity and the role of the latter in the development of T1D. Following is a review of recent literature on the attachment in patients with T1D with a conclusion of a proposed role of attachment organization in the etiology of T1D.  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