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   3739篇
  免费   198篇
  国内免费   20篇
耳鼻咽喉   20篇
儿科学   128篇
妇产科学   76篇
基础医学   537篇
口腔科学   130篇
临床医学   295篇
内科学   854篇
皮肤病学   36篇
神经病学   352篇
特种医学   133篇
外科学   698篇
综合类   16篇
预防医学   140篇
眼科学   25篇
药学   298篇
中国医学   18篇
肿瘤学   201篇
  2023年   20篇
  2022年   22篇
  2021年   83篇
  2020年   55篇
  2019年   79篇
  2018年   101篇
  2017年   74篇
  2016年   82篇
  2015年   87篇
  2014年   124篇
  2013年   190篇
  2012年   257篇
  2011年   249篇
  2010年   120篇
  2009年   125篇
  2008年   200篇
  2007年   247篇
  2006年   239篇
  2005年   169篇
  2004年   164篇
  2003年   164篇
  2002年   147篇
  2001年   120篇
  2000年   125篇
  1999年   87篇
  1998年   32篇
  1997年   30篇
  1996年   22篇
  1995年   22篇
  1994年   15篇
  1992年   37篇
  1991年   45篇
  1990年   48篇
  1989年   36篇
  1988年   35篇
  1987年   39篇
  1986年   24篇
  1985年   28篇
  1984年   22篇
  1983年   22篇
  1981年   10篇
  1980年   10篇
  1979年   17篇
  1978年   10篇
  1977年   13篇
  1976年   11篇
  1974年   12篇
  1973年   9篇
  1972年   11篇
  1965年   10篇
排序方式: 共有3957条查询结果,搜索用时 302 毫秒
1.
2.
3.
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   
4.
5.
The personal experience on the gastric cancer prognosis is reported. Particularly it is outlined that survival is strictly dependent on the wall invasion and lymph-node metastasis. Moreover in cancers with the same wall invasion the prognosis changes very much in relation to lymph-nodal status.  相似文献   
6.
The effects of diet on inflammation: emphasis on the metabolic syndrome.   总被引:3,自引:0,他引:3  
Reducing the incidence of coronary heart disease with diet is possible. The main dietary strategies include adequate omega-3 fatty acids intake, reduction of saturated and trans-fats, and consumption of a diet high in fruits, vegetables, nuts, and whole grains and low in refined grains. Each of these strategies may be associated with lower generation of inflammation. This review examines the epidemiologic and clinical evidence concerning diet and inflammation. Dietary patterns high in refined starches, sugar, and saturated and trans-fatty acids, poor in natural antioxidants and fiber from fruits, vegetables, and whole grains, and poor in omega-3 fatty acids may cause an activation of the innate immune system, most likely by an excessive production of proinflammatory cytokines associated with a reduced production of anti-inflammatory cytokines. The whole diet approach seems particularly promising to reduce the inflammation associated with the metabolic syndrome. The choice of healthy sources of carbohydrate, fat, and protein, associated with regular physical activity and avoidance of smoking, is critical to fighting the war against chronic disease. Western dietary patterns warm up inflammation, while prudent dietary patterns cool it down.  相似文献   
7.
Conflicting published data regarding the role of macrophages and other cell types during the early stages of diabetes mellitus led us to further study this problem. To this end we diabetized mice, using low doses of streptozocin (STZ), 40 mg/kg body wt/day/5 days, and processed their pancreatic tissue for immunocytochemistry and ultrastructural observations; immunohistochemistry was performed on days 5 and 18 after the first STZ injection, and islets were observed ultrastructurally on days 5, 9, 10, and 18. Animals were tested for fasting serum glucose, and isolated islets were assayed for insulin secretion capacity. Immunohistology demonstrated that expression of major histocompatability complex class 2 antigens is strongly induced by multiple, low dose STZ treatments prior to impaired insulin release, and that different types of cells within the islet are capable of expressing Ia molecules. Ultrastructurally we found (a) a small number of macrophages (most probably resident monocytes/macrophages) containing B-cell debris, that were located close to either damaged or intact B cells; (b) a large number of recruited macrophages in a vascular or perivascular position; and (c) macrophages recognizable in the exocrine portion, close to the islets, occasionally containing exocrine cell debris. This led us to believe that recruited macrophages play an important role in the early islet-infiltrating stage.  相似文献   
8.
9.
10.
In rats, oxygen consumption is reduced by about 40-50% 24 h after bilateral nephrectomy. This is also the case when the animals are pretreated with triiodothyronine, 3 x 0.75 mg/kg body weight orally, for 2-3 days. Indole, cresol, putrescine, methylguanidine or acetoine was given intraperitoneally to normal rats at doses of between 5 and 300 mg/kg body weight. Only low single doses of indole (5 mg/kg) reduced oxygen consumption significantly. Single doses of the other substances studied were ineffective even at tenfold higher doses. Some combinations of these substances, however, (10 mg/kg each), reduced the metabolic rate significantly. In contrast to the results in vivo, plasma of uremic rats, as well as the uremic toxins, dissolved in Krebs-phosphate buffer pH 7.4 at concentrations of 30 mg/dl each, had no influence on respiration of rat diaphragma or liver slices in vitro (single substances and different combinations).  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