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   687篇
  免费   37篇
  国内免费   36篇
耳鼻咽喉   3篇
儿科学   53篇
妇产科学   8篇
基础医学   72篇
口腔科学   20篇
临床医学   92篇
内科学   165篇
皮肤病学   8篇
神经病学   18篇
特种医学   162篇
外科学   36篇
综合类   13篇
预防医学   24篇
眼科学   8篇
药学   44篇
肿瘤学   34篇
  2024年   2篇
  2022年   2篇
  2021年   5篇
  2020年   3篇
  2019年   6篇
  2018年   11篇
  2017年   7篇
  2016年   4篇
  2015年   7篇
  2014年   12篇
  2013年   20篇
  2012年   11篇
  2011年   13篇
  2010年   38篇
  2009年   38篇
  2008年   15篇
  2007年   32篇
  2006年   12篇
  2005年   22篇
  2004年   7篇
  2003年   5篇
  2002年   11篇
  2001年   12篇
  2000年   5篇
  1999年   8篇
  1998年   48篇
  1997年   47篇
  1996年   45篇
  1995年   42篇
  1994年   42篇
  1993年   27篇
  1992年   5篇
  1991年   13篇
  1990年   13篇
  1989年   26篇
  1988年   27篇
  1987年   14篇
  1986年   15篇
  1985年   10篇
  1984年   7篇
  1983年   6篇
  1982年   10篇
  1981年   8篇
  1980年   11篇
  1979年   7篇
  1978年   6篇
  1977年   10篇
  1976年   6篇
  1975年   3篇
  1969年   2篇
排序方式: 共有760条查询结果,搜索用时 15 毫秒
1.
2.
Needle core biopsy guided with mammography: a study of cost- effectiveness   总被引:2,自引:0,他引:2  
Lindfors  KK; Rosenquist  CJ 《Radiology》1994,190(1):217
  相似文献   
3.
Forty conventional radiographs with examples of mild interstitial infiltrates and subtle pneumothoraces and 40 normal studies of the chest were selected and digitized, with pixel sizes of 1.0, 0.5, 0.2, and 0.1 mm. Observer performance tests were carried out using receiver operating characteristic analysis. Conventional radiographs and digitized images were compared. The results indicate that, in such cases, diagnostic accuracy increases significantly as the pixel size is reduced, at least to the 0.1-mm level. We conclude that, for digital systems using screen-film or similar image receptors, use of a pixel size substantially larger than 0.1 mm may result in some loss of diagnostic accuracy.  相似文献   
4.
Background: Spherophakia is an uncommon diagnosis. This is the first case report of spherophakia evaluated by ultrasound biomicroscopy.
Methods: Ultrasound biomicroscopy is a new diagnostic technique developed by one of the authors and provides images with microscopic resolution of the anterior segment. A patient with spherophakia was evaluated by ultrasound biomicroscopy (Zeiss-Humphrey, 50MHz) before and after YAG laser iridotomy.
Results: Ultrasound biomicroscopic assessment revealed a shallow anterior chamber, a very steep anterior lens curvature, iridolenticular contact, elongated zonules, and an increased distance between the lens equator and the ciliary processes. Angle closure glaucoma was due to a pupil block mechanism. The pupil block was relieved by YAG laser iridotomy.
Conclusions: Ultrasound biomicroscopy is a useful technique to confirm the diagnosis of spherophakia. The pupil block in spherophakia is relieved by YAG laser iridotomy.  相似文献   
5.
6.
7.
8.
The development of both adenocarcinoma of the jejunum and in situ squamous carcinoma of the oesophagus in an adult coeliac patient is described. Good evidence that adenocarcinoma of jejunum occurs more frequently in patients with coeliac disease has recently become available though this association has been suggested for some time. While oesophageal carcinoma has long been associated with coeliac disease, in situ carcinoma of oesophagus has not been previously described in these circumstances. We feel that the risk of this complication, as calculated from published series, warrants a screening programme for oesophageal malignancy in adult coeliacs.  相似文献   
9.
Background: Classic theories descibe that the common pulmonary vein develops as an outgrowth from either the sinus venosus or atrial segment. Recent studies show that the pulmonary veins are connected to the sinu-atrial region before its differentiation into a sinus venosus and atrial segment. Methods: The development of the sinu-atrial region with regard to the developing common pulmonary vein and the growth of the atrial septum was investigated in avian embryos, using both scanning electron microscopy and immunohistochemistry. Embryos ranging between stage HH12 and HH28 were incubated with QH-1 that recognizes quail endothelial cells and precursors, HNK-1, that appears in this study to detect the myocardium of the sinus venosus, or with HHF-35, being specific for muscle actins. Also vascular casts of the heart were produced by injecting prepolymerized Mercox into the vascular system. Results: In preseptation stages the common pulmonary vein drains into the left part of the sinus venosus, that is clearly demarcated by the sinuatrial fold and HNK-1 expression. During atrial septation the left part of the sinus venosus, in contrast to the right part, loses its HNK-1 antigen from stage HH23 onwards, while at the same time the sinu-atrial fold in the left atrial dorsal wall flattens and disappears. From stage HH25 onwards HNK-1 expression is restricted to the right part of the sinus venosus, which contributes to the right atrium. The myocardial atrial septum never expresses the HNK-1 antigen, suggesting that the septum is of atrial origin. Discussion: It appeared that the sinus venosus does not only contribute to the sinus venarum of the right atrium, but also to the left atrium. © 1995 Wiley-Liss, Inc.  相似文献   
10.
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