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   1513499篇
  免费   104411篇
  国内免费   3389篇
耳鼻咽喉   20870篇
儿科学   49204篇
妇产科学   41388篇
基础医学   222785篇
口腔科学   42152篇
临床医学   131052篇
内科学   297500篇
皮肤病学   33101篇
神经病学   114324篇
特种医学   58615篇
外国民族医学   405篇
外科学   232385篇
综合类   32336篇
现状与发展   2篇
一般理论   393篇
预防医学   109891篇
眼科学   34591篇
药学   111363篇
  3篇
中国医学   3934篇
肿瘤学   85005篇
  2018年   15708篇
  2017年   12292篇
  2016年   13510篇
  2015年   15225篇
  2014年   21144篇
  2013年   32373篇
  2012年   43138篇
  2011年   45681篇
  2010年   27502篇
  2009年   25990篇
  2008年   43262篇
  2007年   46248篇
  2006年   46686篇
  2005年   45086篇
  2004年   43515篇
  2003年   41803篇
  2002年   40988篇
  2001年   72134篇
  2000年   73824篇
  1999年   62219篇
  1998年   16833篇
  1997年   14931篇
  1996年   15034篇
  1995年   14204篇
  1994年   13303篇
  1993年   12375篇
  1992年   48045篇
  1991年   46863篇
  1990年   45842篇
  1989年   44585篇
  1988年   40983篇
  1987年   40165篇
  1986年   38433篇
  1985年   36298篇
  1984年   26939篇
  1983年   22957篇
  1982年   13320篇
  1979年   24821篇
  1978年   17400篇
  1977年   14731篇
  1976年   14077篇
  1975年   15479篇
  1974年   18345篇
  1973年   17504篇
  1972年   16518篇
  1971年   15328篇
  1970年   14769篇
  1969年   13749篇
  1968年   12918篇
  1967年   11812篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
OBJECTIVES: To evaluate a novel method for localization of subdural electrodes in presurgical assessment of patients with drug-resistant focal epilepsy. METHODS: We studied eight consecutive patients with posterior epilepsy in whom subdural electrodes were implanted for presurgical evaluation. Electrodes were detected on post-implantation brain CT scans through a semiautomated procedure based on a MATLAB routine. Then, post-implantation CT scans were fused with pre-implantation MRI to localize the electrodes in relation to the underlying cortical structures. The reliability of this procedure was tested by comparing 3D-rendered MR images of the electrodes with electrode position as determined by intraoperative digital photography. RESULTS: In each patient, all electrodes could be correctly localized and visualized in a stereotactic space, thus allowing optimal surgery planning. The agreement between the procedure-generated images and the digital photographs was good according to two independent raters. The mean mismatch between the 3D images and the photographs was 2 mm. CONCLUSIONS: While our findings need confirmation on larger samples including patients with anterior epilepsy, this procedure allowed to localize subdural electrodes and to establish the spatial relationship of each electrode to the underlying brain structure, either normal or damaged, on brain convessity, basal and medial cortex. SIGNIFICANCE: Being simple, rapid, unexpensive, and reliable, this procedure holds promise to be useful to optimize epilepsy surgery planning.  相似文献   
32.
Abstract Guillain-Barré syndrome (GBS) is a disease of the peripheral nervous system, which is caused by aberrant immune responses directed against some components of peripheral nerves. GBS is rarely accompanied by cardiovascular involvement. We describe a case of acute neuropathy complicated by sudden heart failure and left ventricular dysfunction which had a presumably neurogenic origin. Pathogenesis of acute heart failure is probably due to transitorial stunned myocardium and neurogenic cardiac injury. We show a rare case of transitorial and acute cardiac dysfunction by echocardiography and laboratory markers of heart failure.  相似文献   
33.
34.
35.
36.
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   
37.
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   
38.
目的:描述胚胎种植前遗传诊断在1例携带Ⅰ型白细胞黏附缺陷病(LAD-1)携带者并完成健康妊娠夫妇中的应用。设计:病例报道。机构:大学医院生殖中心。患者:1例男女双方都是LAD-1携带者的夫妇,女方CD18基因的外显子4携带有G400A置换,男方的外显子5携带有C562T置换。干预:标准体外受精(IVF)后第3天行卵裂期活检和分裂球遗传分析以检测2处突变以及21号染色体标记物。主要观察指标:1个未罹患LAD-1婴儿的出生。结果:得到15个卵母细胞,其中10个受精。8个胚胎适宜胚胎活组织检查。  相似文献   
39.
Setting goals to maintain hope.   总被引:3,自引:0,他引:3  
  相似文献   
40.
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