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   1131327篇
  免费   78951篇
  国内免费   3290篇
耳鼻咽喉   15064篇
儿科学   34746篇
妇产科学   30242篇
基础医学   156857篇
口腔科学   28966篇
临床医学   98211篇
内科学   232309篇
皮肤病学   22141篇
神经病学   93810篇
特种医学   44034篇
外国民族医学   346篇
外科学   177010篇
综合类   22268篇
一般理论   557篇
预防医学   84666篇
眼科学   26167篇
药学   79554篇
  6篇
中国医学   2118篇
肿瘤学   64496篇
  2021年   10856篇
  2019年   11251篇
  2018年   14504篇
  2017年   11272篇
  2016年   12253篇
  2015年   14083篇
  2014年   20220篇
  2013年   30151篇
  2012年   42209篇
  2011年   44595篇
  2010年   26308篇
  2009年   24475篇
  2008年   41491篇
  2007年   43747篇
  2006年   43907篇
  2005年   43307篇
  2004年   41247篇
  2003年   39303篇
  2002年   37903篇
  2001年   43299篇
  2000年   44019篇
  1999年   38399篇
  1998年   12801篇
  1997年   11517篇
  1996年   11114篇
  1995年   10360篇
  1994年   9678篇
  1993年   9010篇
  1992年   29346篇
  1991年   28016篇
  1990年   27313篇
  1989年   26209篇
  1988年   24429篇
  1987年   24015篇
  1986年   23092篇
  1985年   22020篇
  1984年   16911篇
  1983年   14520篇
  1982年   9324篇
  1981年   8276篇
  1979年   15228篇
  1978年   10899篇
  1977年   9191篇
  1976年   8664篇
  1975年   9393篇
  1974年   11127篇
  1973年   10556篇
  1972年   9982篇
  1971年   9176篇
  1970年   8809篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
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   
23.
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   
24.
Setting goals to maintain hope.   总被引:3,自引:0,他引:3  
  相似文献   
25.
26.
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   
27.
28.
Photodynamic therapy (PDT) is based on the selective light activation of an exogenously given drug to patients. PDT acts mainly on cell membranes either of neovascular endothelial cells or of cancer cells leading to cancer cell death. Six drugs are now marketed based on clinical assays in various indications, which showed a clear cost efficiency as compared to other classical procedures. PDT is easy to handle and can be performed in medical installations fitting the conditions of health care in developing countries. Its cost effectiveness could represent an appropriate solution to the increasing number of cancers of various origin. However despite all the clinical results now available, PDT development remains slow. The reasons for this situation include cost of development, intellectual property, and competition between pharmaceutical companies.  相似文献   
29.
30.
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