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   1228篇
  免费   46篇
  国内免费   81篇
耳鼻咽喉   1篇
儿科学   67篇
妇产科学   9篇
基础医学   134篇
口腔科学   23篇
临床医学   221篇
内科学   293篇
皮肤病学   33篇
神经病学   27篇
特种医学   300篇
外科学   57篇
综合类   26篇
预防医学   28篇
眼科学   6篇
药学   71篇
肿瘤学   59篇
  2022年   5篇
  2021年   8篇
  2019年   11篇
  2018年   7篇
  2017年   9篇
  2016年   10篇
  2015年   18篇
  2014年   11篇
  2013年   26篇
  2012年   10篇
  2011年   14篇
  2010年   48篇
  2009年   45篇
  2008年   18篇
  2007年   56篇
  2006年   17篇
  2005年   25篇
  2004年   9篇
  2003年   12篇
  2002年   17篇
  2001年   16篇
  2000年   19篇
  1999年   24篇
  1998年   93篇
  1997年   88篇
  1996年   109篇
  1995年   84篇
  1994年   87篇
  1993年   74篇
  1992年   21篇
  1991年   30篇
  1990年   27篇
  1989年   32篇
  1988年   36篇
  1987年   27篇
  1986年   34篇
  1985年   32篇
  1984年   13篇
  1983年   21篇
  1982年   20篇
  1981年   21篇
  1980年   17篇
  1979年   4篇
  1978年   9篇
  1977年   14篇
  1976年   13篇
  1975年   7篇
  1970年   1篇
  1969年   1篇
  1966年   1篇
排序方式: 共有1355条查询结果,搜索用时 78 毫秒
991.
Stenosis of individual pulmonary veins: radiologic findings   总被引:1,自引:0,他引:1  
Congenital stenosis of individual pulmonary veins is uncommon. Of the 49 cases reported, four were seen at the IWK Hospital for Children and are reported here. Plain radiographs show a shift of the heart toward the side of major involvement, Kerley B lines, fluid in the fissures, and interstitial edema of the affected lobes. These findings, while subtle, should nevertheless suggest stenosis. Technetium-99m macro-aggregate lung perfusion scans show absence of or diminished perfusion of the affected lobes. The diagnosis can usually be confirmed with angiography. Congenital stenosis of individual pulmonary veins should be considered in children with repeated pulmonary infections, dyspnea, failure to thrive, hemoptysis, or unexplained pulmonary hypertension.  相似文献   
992.
Distal lateral ventricular atrium: reevaluation of normal range   总被引:5,自引:0,他引:5  
  相似文献   
993.
Summary— First-order elimination of drugs is often assumed in pharmacokinetics and elimination rate constant is then frequently determined by log-linear regression analysis from plasma concentration measurements. When the time which elapses between the first and the last plasma sample is short compared to the decay half-life, the elimination rate constant may not be determined with satisfactory precision, in particular because of analytical error. Application of basic principles of linear regression analysis allowed us to quantify the theoretical effect of analytical error on the determination of the drug elimination rate constant in that situation. It was highlighted that the precision of that determination could be efficiently improved by measuring samples in replicate, which should be recommended in practice. A user-friendly program was developed which can be used prospectively to optimize sampling strategy, and retrospectively to estimate the precision of parameter estimates. The program works on IBM PC and compatible microcomputers and is available on request.  相似文献   
994.
Inflammation: imaging with Tc-99m HMPAO-labeled leukocytes   总被引:9,自引:0,他引:9  
Leukocytes labeled with technetium-99m hexamethylpropyleneamine oxime (HMPAO) were used in 100 patients: 32 with suspected inflammatory bowel disease, 17 with fever of unknown origin, 21 with suspected abdominal sepsis, 20 with suspected bone sepsis, seven with bronchiectasis, and three with recent myocardial infarction. The distribution of activity in patients subsequently shown not to have inflammatory bowel disease was similar to that previously described for indium-111-labeled leukocytes. However, in this study, activity was also seen in the kidneys and bladder and occasionally the gallbladder on both early (1-3 hours) and late (24 hours) views, and in the colon in late views. Migration of Tc-99m-labeled granulocytes was seen in inflammatory disease as early as 30 minutes after injection, while normal bowel activity was not seen before 4 hours. The sensitivity of Tc99m-labeled leukocytes in the detection of inflammation was 100%, the specificity was 95%.  相似文献   
995.
Central venous occlusion: MR angiography   总被引:2,自引:0,他引:2  
  相似文献   
996.
研究了6种氯代萘磺酰胺衍生物对细菌脂多糖(LPS)诱导经卡西霉素A23187体外激活的巨噬细胞分泌肿瘤坏死因子(TNF)作用的影响。表明:将氯代萘磺酰胺的氨基接以亲水性不同长度碳链的胺基,所得衍生物可明显抑制LPS诱生TNF的作用;接以疏水性烷基,则可明显增强亚适剂量的LPS诱生TNF的作用,且碳链长度对化合物的作用强度有一定的影响。  相似文献   
997.
Sheath needle for liver biopsy in high-risk patients   总被引:1,自引:0,他引:1  
Chuang  VP; Alspaugh  JP 《Radiology》1988,166(1):261
  相似文献   
998.
Arterial vascularisation of the extrahepatic biliary tract   总被引:1,自引:0,他引:1  
Summary The aim of this study was to establish a plan of the arterial distribution to the main supraduodenal biliary tract in order to draw practical conclusions for biliary surgery, especially in bilio-alimentary and biliobiliary anastomoses and liver transplantation. It was based on a study of 60 fresh subjects and was carried out using four different methods: dissection after injection of colored latex into the superior mesenteric a. (10 subjects), radiography and dissection after injection of Micropaque into the celiac trunk (10), dissection after injection of Indian ink into the common hepatic a. (10) and radiography and dissection after selective injection of the right hepatic a. or the gastroduodenal a. (30). Analysis of the results leads to definition of three types of vascularisation and two territories, superior and inferior, overlapping at the level of the mouth of the cystic duct. The practical implications for biliary surgery and liver transplantation are discussed.This study was made with the aid of a grant from the Fondation Martine Midy.  相似文献   
999.
The portacaval space: CT with MR correlation   总被引:6,自引:0,他引:6  
Between the portal vein and the inferior vena cava lies a small space that may be occupied by multiple anatomic structures including the caudate and papillary processes of the caudate lobe of the liver, portacaval lymph nodes, replaced or accessory right hepatic arteries, posterosuperior pancreaticoduodenal vessels, the cystic duct, and the epiploic foramen to the lesser sac. The sectional anatomy of these structures is illustrated in this paper with particular emphasis on the portacaval nodes. Unlike the adjacent celiac lymph nodes, portacaval nodes appear rectangular or elliptical on transverse sections and may measure up to 1.3 cm in anteroposterior dimension. They may mimic portions of the pancreas, liver, or biliary tract on sectional images.  相似文献   
1000.
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