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   4692篇
  免费   516篇
  国内免费   48篇
耳鼻咽喉   49篇
儿科学   175篇
妇产科学   100篇
基础医学   347篇
口腔科学   55篇
临床医学   592篇
内科学   1121篇
皮肤病学   93篇
神经病学   437篇
特种医学   884篇
外科学   569篇
综合类   56篇
一般理论   2篇
预防医学   172篇
眼科学   251篇
药学   137篇
中国医学   3篇
肿瘤学   213篇
  2023年   55篇
  2021年   51篇
  2020年   102篇
  2019年   43篇
  2018年   133篇
  2017年   100篇
  2016年   94篇
  2015年   91篇
  2014年   134篇
  2013年   187篇
  2012年   164篇
  2011年   147篇
  2010年   131篇
  2009年   162篇
  2008年   150篇
  2007年   150篇
  2006年   175篇
  2005年   177篇
  2004年   157篇
  2003年   132篇
  2002年   138篇
  2001年   139篇
  2000年   124篇
  1999年   132篇
  1998年   132篇
  1997年   132篇
  1996年   100篇
  1995年   109篇
  1994年   76篇
  1993年   74篇
  1992年   94篇
  1991年   99篇
  1990年   91篇
  1989年   134篇
  1988年   110篇
  1987年   134篇
  1986年   104篇
  1985年   84篇
  1984年   60篇
  1983年   42篇
  1982年   36篇
  1981年   35篇
  1979年   52篇
  1977年   38篇
  1976年   45篇
  1975年   40篇
  1974年   33篇
  1973年   29篇
  1971年   35篇
  1970年   28篇
排序方式: 共有5256条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
CT evaluation of Crohn's disease: effect on patient management   总被引:8,自引:0,他引:8  
CT scans from 80 consecutive patients with clinically symptomatic Crohn's disease were reviewed retrospectively to determine the effect of CT diagnosis on patient management. The initial clinical impression and any subsequent change in patient management because of the CT findings were noted. In 22 (28%) of the 80 patients, significant previously unsuspected findings led to a change in medical or surgical management. These included 12 patients with fistulae, four with abscess, two with avascular necrosis of the femoral head, two with sacral osteomyelitis, and single cases of pelvic inflammatory disease and femoral vein thrombosis.  相似文献   
5.
The computed tomography findings in two cases of gastrointestinal superinfection by opportunistic organisms in acquired immune deficiency syndrome are presented. Findings included thickening of the mucosal folds and the bowel wall in the small intestine and colon associated with cytomegalovirus and cryptosporidiosis. These cases indicate that it is important to look carefully at the gastrointestinal tract when performing computed tomography in this group of patients. Unsuspected bowel pathology may be demonstrated, or disease may be confirmed in clinically suspected cases.  相似文献   
6.
Extrahepatic portal vein thrombosis (EHPVT) may occur in children or adults and usually comes to clinical attention due to complications of portal hypertension such as variceal hemorrhage. A variety of standard surgical techniques exist to manage these patients, but when these fail surgical options are limited. We describe two novel portosystemic shunts that utilize the gonadal vein as an autologous conduit. Four patients were evaluated for EHPVT with variceal bleeding. None of the patients were candidates for a standard splenorenal shunt due to prior surgical procedures. The first patient underwent a left mesogonadal shunt and the remaining 3 patients underwent a right mesogonadal shunt. Postoperative ultrasound or computed tomography (CT) scan confirmed early patency of the shunt in each patient. There have been no further episodes of variceal hemorrhage with follow-up of 3.5 years in the child who underwent the left mesogonadal shunt, and 17, 19, and 20 months in the patients who underwent the right mesogonadal shunt. Three of the 4 shunts remain patent. One shunt thrombosis occurred in a patient homozygous for the Factor V Leiden mutation despite anticoagulation with coumadin. This is the first report of the successful use of the gonadal vein as an in situ conduit for constructing a portosystemic shunt. In conclusion, the right and left mesogonadal shunts may be useful as salvage operations for patients with EHPVT who have failed standard surgical shunt procedures.  相似文献   
7.
8.
9.
Cultured brain cells from rat fetuses of ethanol-treated mothers demonstrated more than 2-fold elevations in choline acetyltransferase (ChAT) activity relative to those of control (saline-exposed) fetal brain cells. When cells from control animals were incubated in vitro for 5 days with 0.1% ethanol, ChAT activity was found to increase more than 4-fold. Brain cells from in utero ethanol-treated animals further exposed to ethanol in vitro for 5 days demonstrated significantly higher ChAT activity compared to cells exposed to ethanol only in vivo. These levels were more than 6 times greater than those of central nervous system cells never exposed to ethanol. Acetylcholinesterase (AChE) activity was significantly elevated (greater than 4-fold) in fetal brain cells when ethanol was present both in vivo and in vitro, but neither treatment alone resulted in any significant changes in AChE. These effects of ethanol on enzymes involved in acetylcholine metabolism may contribute to the different developmental neurologic abnormalities associated with fetal alcohol exposure.  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