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   900298篇
  免费   62494篇
  国内免费   2339篇
耳鼻咽喉   12479篇
儿科学   28704篇
妇产科学   26154篇
基础医学   126650篇
口腔科学   24695篇
临床医学   74802篇
内科学   183330篇
皮肤病学   18988篇
神经病学   71471篇
特种医学   36455篇
外国民族医学   336篇
外科学   142188篇
综合类   19030篇
一般理论   247篇
预防医学   64573篇
眼科学   20093篇
药学   63961篇
中国医学   1798篇
肿瘤学   49177篇
  2018年   9063篇
  2017年   7171篇
  2016年   7699篇
  2015年   8737篇
  2014年   12386篇
  2013年   19239篇
  2012年   25696篇
  2011年   27297篇
  2010年   16593篇
  2009年   15812篇
  2008年   26167篇
  2007年   27772篇
  2006年   27953篇
  2005年   27481篇
  2004年   26327篇
  2003年   25498篇
  2002年   25084篇
  2001年   41379篇
  2000年   42574篇
  1999年   36285篇
  1998年   9977篇
  1997年   9155篇
  1996年   9093篇
  1995年   8452篇
  1994年   8088篇
  1993年   7585篇
  1992年   28223篇
  1991年   26992篇
  1990年   26415篇
  1989年   25357篇
  1988年   23560篇
  1987年   23182篇
  1986年   22262篇
  1985年   21157篇
  1984年   15811篇
  1983年   13481篇
  1982年   8088篇
  1979年   14589篇
  1978年   10209篇
  1977年   8628篇
  1976年   8149篇
  1975年   8963篇
  1974年   10698篇
  1973年   10184篇
  1972年   9662篇
  1971年   8919篇
  1970年   8586篇
  1969年   8026篇
  1968年   7684篇
  1967年   7086篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
11.
12.
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis.  相似文献   
13.
AIM: Cardiovascular risk factors can be present in children and young adults. We previously found abnormal microvascular function in children who had glucose intolerance and insulin resistance. The aim of the present study was to investigate whether they also have abnormalities in left ventricular mass (LVM) and arterial stiffness. METHODS: We measured heart dimensions and LVM using echocardiography, and arterial stiffness using pulse wave analysis in 23 children with good glucose handling (postfeeding glucose: 3.9 to 5 mmol/L) and 21 with poor glucose handling (7.7 to 11.4 mmol/L). RESULTS: The time to pulse reflection was slightly shorter in the poorer glucose handlers (mean+/-SD: 143+/-10 vs 153+/-20 ms, P=0.04), suggestive of increased arterial stiffness. Also in this group, there were significant relationships between intraventricular septal thickness, blood pressure and body mass index, but not in the normal glucose handlers. CONCLUSIONS: We have found that normal children who are in the lowest quintile of glucose tolerance in comparison with their peers are exhibiting the first signs of arterial stiffening. In addition, we have seen the beginnings of a relationship between blood pressure, body mass index and left ventricular enlargement in this group. While these changes may not yet be clinically significant, their emergence might be further evidence of early predisposition to cardiovascular disease.  相似文献   
14.
Setting goals to maintain hope.   总被引:3,自引:0,他引:3  
  相似文献   
15.
16.
Sniff nasal inspiratory pressure (SNIP) measurement is a volitional noninvasive assessment of inspiratory muscle strength. A maximum of 10 sniffs is generally used. The purpose of the present study was to investigate whether the maximum SNIP improved after the tenth sniff. In total, 20 healthy volunteers and 305 patients with various neuromuscular and lung diseases were encouraged to perform 40 and 20 sniffs, respectively. The best SNIP among the first 10 sniffs was lower than the best SNIP among the next 10 sniffs in the healthy volunteers and patients. The SNIP improvement after the twentieth sniff was marginal. In conclusion, a learning effect persists after the tenth sniff. The current authors suggest using 10 additional sniffs when the best result of the first 10 sniffs is slightly below normal, or when sniff nasal inspiratory pressure is used to monitor a progressive decline in inspiratory muscle strength.  相似文献   
17.
18.
19.
20.
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