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   1379篇
  免费   105篇
  国内免费   79篇
耳鼻咽喉   1篇
儿科学   46篇
妇产科学   11篇
基础医学   132篇
口腔科学   15篇
临床医学   157篇
内科学   513篇
皮肤病学   28篇
神经病学   19篇
特种医学   297篇
外科学   94篇
综合类   21篇
预防医学   27篇
眼科学   1篇
药学   159篇
肿瘤学   42篇
  2023年   2篇
  2022年   3篇
  2021年   13篇
  2020年   13篇
  2019年   15篇
  2018年   23篇
  2017年   18篇
  2016年   15篇
  2015年   16篇
  2014年   26篇
  2013年   37篇
  2012年   40篇
  2011年   38篇
  2010年   42篇
  2009年   47篇
  2008年   48篇
  2007年   91篇
  2006年   34篇
  2005年   38篇
  2004年   28篇
  2003年   40篇
  2002年   21篇
  2001年   45篇
  2000年   32篇
  1999年   41篇
  1998年   79篇
  1997年   77篇
  1996年   55篇
  1995年   75篇
  1994年   41篇
  1993年   41篇
  1992年   40篇
  1991年   28篇
  1990年   22篇
  1989年   45篇
  1988年   44篇
  1987年   28篇
  1986年   29篇
  1985年   47篇
  1984年   19篇
  1983年   13篇
  1982年   25篇
  1981年   14篇
  1980年   24篇
  1979年   5篇
  1978年   4篇
  1977年   14篇
  1976年   16篇
  1975年   9篇
  1969年   1篇
排序方式: 共有1563条查询结果,搜索用时 437 毫秒
121.
A prospective evaluation of color flow mapping and real-time ultrasound was performed to determine if pseudoaneurysms could be distinguished from other causes of masses surrounding vascular grafts of the lower extremities. Twelve palpable pulsatile masses were imaged. Diagnoses were confirmed at angiography (n = 11), computed tomography (n = 7), aspiration biopsy (n = 5), and operative intervention (n = 6). A swirling pattern of blood flow was seen in six of seven cases of pseudoaneurysm. Lack of flow signals was noted in four of the five collections representing hematoma (n = 2) or infection (n = 2). The seventh case was later shown to be an infected, thrombosed pseudoaneurysm. The single false-positive diagnosis was made early in the series when the flow signals detected were due to transmitted arterial pulsations. The authors conclude that color Doppler flow imaging is useful in the differential diagnosis of pulsatile masses associated with prosthetic grafts. Prosthetic graft pseudoaneurysms have a specific appearance of swirling blood flow arising from a wide neck and are distinguishable from traumatic or iatrogenic pseudoaneurysms of the native vascular tree.  相似文献   
122.
Ratcliffe  J; Tait  J; Lisle  D; Leditschke  JF; Bell  J 《Radiology》1989,171(3):827-830
Segmental dilatation of the small bowel is a rare congenital abnormality that occurs mainly in children and produces significant nonspecific symptoms. The authors reviewed 33 cases reported in the literature and present three new cases in which the lesion was demonstrated on radiographs obtained before laparotomy. These cases showed the spectrum of symptoms and characteristic radiologic features of this condition in both plain abdominal radiographs and barium studies. Plain radiographs of the abdomen may show an isolated loop of bowel containing an air-fluid level. The characteristic finding in barium studies of the small bowel is a localized dilatation of the small bowel lumen with afferent and efferent loops. In the absence of a complication or coexistent cause of obstruction, the transit time of contrast medium through the small bowel is not delayed. The radiologic examination is useful in diagnosis, and the condition is cured with surgery.  相似文献   
123.
124.
125.
126.
Burt  TB; Seeger  JF; Carmody  RF; Yang  PJ 《Radiology》1986,158(2):546-547
Inward buckling of the dura at C1-2 may occasionally occur with hyperextension of the neck and can result in a difficult or unsuccessful puncture when the posterior lateral C1-2 approach is used for cervical myelography. In this circumstance, placement of the head in a neutral or slightly flexed position may widen the posterior subarachnoid space and facilitate the needle puncture.  相似文献   
127.
Congenital abnormalities of the aortic arch: MR imaging   总被引:1,自引:0,他引:1  
Gomes  AS; Lois  JF; George  B; Alpan  G; Williams  RG 《Radiology》1987,165(3):691-695
Thirty-four patients, 1 month to 63 years old, with known or suspected congenital abnormalities of the aortic arch underwent magnetic resonance (MR) imaging. Sixteen patients were studied retrospectively, 18 prospectively. In all retrospective studies, the aortic arch abnormality was seen with MR imaging. In the prospective studies, MR imaging enabled diagnosis in 15 of 18 (83%) patients. Twenty-nine of 34 patients underwent two-dimensional echocardiography; nine were studied retrospectively, 20 prospectively. In the prospective studies, echocardiography enabled diagnosis in 13 of 20 (65%) patients. Although two-dimensional echocardiography has a high sensitivity in the detection of aortic arch abnormalities in the neonate, arch abnormalities in the neonate, its sensitivity is lower in older children, adults, and postoperative patients. The authors' experience shows that MR imaging is an important, noninvasive modality in the evaluation of older children, adults, and postoperative patients with congenital aortic arch abnormalities.  相似文献   
128.
129.
130.
Anxiety in patients undergoing MR imaging   总被引:6,自引:0,他引:6  
Quirk  ME; Letendre  AJ; Ciottone  RA; Lingley  JF 《Radiology》1989,170(2):463-466
To determine and quantify the major sources of anxiety for patients undergoing magnetic resonance (MR) imaging and to suggest means by which to eliminate or diminish their negative effects, the authors studied anxiety in 46 subjects. Of these, 20 randomly selected subjects who successfully completed the examination participated in exit interviews. Six subjects who terminated the examination before completion also completed exit interviews. Pre-imaging and postimaging questionnaires (state-trait anxiety inventory) were administered to measure anxiety in the 20 other subjects. Anxiety was associated with the constrictive dimensions of the magnet bore, examination duration, coil noise, and temperature within the bore. Preparation at the point of referral was consistently absent, incomplete, or misleading. Patients used identifiable strategies to cope with the examination: blinding, breathing relaxation techniques, visualization of pleasant images, and performance of mental exercises.  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