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   426篇
  免费   26篇
  国内免费   19篇
儿科学   7篇
妇产科学   6篇
基础医学   77篇
口腔科学   8篇
临床医学   35篇
内科学   98篇
皮肤病学   5篇
神经病学   13篇
特种医学   106篇
外科学   15篇
综合类   19篇
预防医学   11篇
药学   33篇
肿瘤学   38篇
  2020年   2篇
  2019年   2篇
  2018年   3篇
  2017年   3篇
  2016年   8篇
  2015年   7篇
  2014年   9篇
  2013年   8篇
  2012年   12篇
  2011年   12篇
  2010年   9篇
  2009年   9篇
  2008年   17篇
  2007年   28篇
  2006年   16篇
  2005年   17篇
  2004年   19篇
  2003年   10篇
  2002年   11篇
  2001年   8篇
  2000年   15篇
  1999年   9篇
  1998年   17篇
  1997年   22篇
  1996年   12篇
  1995年   11篇
  1994年   13篇
  1993年   9篇
  1992年   3篇
  1991年   4篇
  1990年   3篇
  1989年   18篇
  1988年   8篇
  1987年   10篇
  1986年   14篇
  1985年   15篇
  1984年   7篇
  1983年   3篇
  1982年   11篇
  1981年   6篇
  1980年   9篇
  1978年   3篇
  1977年   3篇
  1976年   5篇
  1975年   2篇
  1940年   2篇
  1929年   2篇
  1926年   2篇
  1922年   4篇
  1918年   2篇
排序方式: 共有471条查询结果,搜索用时 31 毫秒
51.
Background: Ultrasound-guided biopsies of abdominal organs are not without risks for the patients; in particular, hemorrhagic complications may occur. Thus, over the last few years, automatic biopsy guns have been developed to facilitate the biopsy process. Methods: The aim of our retrospective study was to examine the quality of specimens and the complication rate of ultrasound-guided biopsies of abdominal organs carried out in our institution using the automatic Autovac biopsy system during a period of 1.5 years. Of the total number of 321 biopsies, 290 were performed with the 1.2-mm Autovac needle, and in 31 cases the 0.95-mm needle was used. Among the 321 biopsies there were 211 of the liver parenchyma (66%), 47 of a liver tumor (14%), 38 of the pancreas (12%), 15 of the kidney parenchyma (5%), and 10 of a retroperitoneal tumor (3%). Results: In 310 of the 321 biopsies it was possible to obtain sufficient diagnostically usable material for the pathologist (96.6%). In the other 11 cases the material obtained did not enable proper histologic diagnosis (3.4%). Two of these 11 biopsies were carried out with the 0.95-mm needle, and the other 9 with the 1.2-mm needle.Twenty-four hours after the biopsy each patient underwent routine ultrasound examination to exclude a possible bleeding. In eight cases an afterbleeding occurred (total hemorrhagic rate, 2.5%), four times without clinical consequences. The other four bleeding complications were more serious (1.2% of all taps), and all occurred after liver biopsies in patients with a history of liver complaints and abnormal clotting variables. There were no fatalities among our biopsies (mortality rate, 0%). Conclusion: The automatic Autovac biopsy system is suitable and relatively safe for obtaining sufficient histopathologic material from intra-abdominal organs.  相似文献   
52.
Jolles  PR; Shin  MS; Jones  WP 《Radiology》1986,159(3):647-651
A retrospective morphologic study of 80 cases was undertaken to determine factors affecting detectability of computed tomographically (CT) proved aortopulmonary (AP) window lesions on conventional posteroanterior (PA) and lateral chest radiographs. Criteria used for determining abnormality were: solitary lymph node enlargement over 1.5 cm or three or more 1-cm nodes and obvious large masses or vascular anomalies. CT scans and corresponding PA and lateral radiographs were analyzed for lesion detectability, size, and location. In 49% of cases there was no detectable lesion in the AP window on radiographs; a definite AP window lesion was seen in 41%, and 10% were equivocal. Major contributing factors to low detectability of AP window lesions on radiographs include size and, more important, location of the lesion. An additional 45 cases of CT-proved normal AP windows were retrospectively reviewed to determine the false-positive rate of PA and lateral radiographs in detection of AP window lesions: 43 (96%) were classified as negative, the remaining two (4%) as equivocal. Although the AP window is a small space, it is the site of many pathologic conditions; the study results indicate that CT may be an essential procedure for its evaluation.  相似文献   
53.
Six normal and 16 neoplastic colorectal specimens were examined with 8.5-MHz ultrasound (US). An articulated system facilitated precise spatial correlation between US and histologic sections. Images were blindly interpreted and then compared with histologic results. All six normal specimen showed five distinct echo layers and were distinguished from neoplastic specimens by all the observers. The central echogenic layer, corresponding to the submucosa, is useful in determining the depth of origin of a neoplasm and the presence of submucosal invasion. US had an accuracy of 92.5% in demonstrating invasion of the submucosa and 77% for invasion of the muscularis externa. For mucosal neoplasms with invasion through the muscularis externa and extension into the subserosal tissues, nearly 90% of US interpretations were correct. High-frequency US may be useful in determining the depth of invasion of mucosal tumors with respect to the submucosa and in differentiating mucosal from extramural masses.  相似文献   
54.
55.
56.
57.
58.
59.
60.
Sclerosing cholangitis: CT findings   总被引:5,自引:0,他引:5  
The value of computed tomography (CT) in the detection of primary sclerosing cholangitis (PSC) in the intrahepatic and extrahepatic biliary systems was assessed by comparing CT scans of 20 cases of PSC with cholangiographic findings. In 16 of 19 cases of extrahepatic duct disease demonstrated with cholangiography, CT demonstrated abnormalities of the common hepatic duct, or bile duct, including duct stenosis, mural nodularity, duct dilatation, wall thickening, and mural enhancement. CT demonstrated intrahepatic disease in all 20 cases, including duct dilatation, duct stenosis, pruning, and beading. CT was superior to cholangiography in characterization of the status of the intrahepatic duct system in 11 of 20 cases. In addition, CT demonstrated extrabiliary complications of PSC in 12 cases and superimposed cholangiocarcinoma in three cases. While cholangiography remains the standard for diagnosis and follow-up of PSC, CT can provide valuable information about the extent and complications of the disease.  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