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   1783篇
  免费   116篇
  国内免费   11篇
耳鼻咽喉   15篇
儿科学   70篇
妇产科学   35篇
基础医学   176篇
口腔科学   30篇
临床医学   237篇
内科学   454篇
皮肤病学   15篇
神经病学   73篇
特种医学   184篇
外科学   251篇
综合类   26篇
预防医学   96篇
眼科学   23篇
药学   127篇
中国医学   8篇
肿瘤学   90篇
  2023年   9篇
  2022年   11篇
  2021年   19篇
  2020年   12篇
  2019年   22篇
  2018年   24篇
  2017年   13篇
  2016年   27篇
  2015年   31篇
  2014年   37篇
  2013年   41篇
  2012年   64篇
  2011年   72篇
  2010年   50篇
  2009年   45篇
  2008年   79篇
  2007年   70篇
  2006年   95篇
  2005年   69篇
  2004年   65篇
  2003年   65篇
  2002年   65篇
  2001年   50篇
  2000年   61篇
  1999年   45篇
  1998年   50篇
  1997年   69篇
  1996年   49篇
  1995年   42篇
  1994年   40篇
  1993年   30篇
  1992年   45篇
  1991年   31篇
  1990年   29篇
  1989年   46篇
  1988年   41篇
  1987年   34篇
  1986年   37篇
  1985年   31篇
  1984年   24篇
  1983年   17篇
  1982年   22篇
  1981年   9篇
  1980年   10篇
  1979年   7篇
  1978年   10篇
  1977年   15篇
  1976年   11篇
  1975年   9篇
  1973年   12篇
排序方式: 共有1910条查询结果,搜索用时 15 毫秒
1.
2.
Ruggieri  PM; Laub  GA; Masaryk  TJ; Modic  MT 《Radiology》1989,171(3):785-791
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.  相似文献   
3.
Paediatric dacryocystorhinostomy   总被引:1,自引:0,他引:1  
Of 258 cases of dacryocystorhinostomy performed on children in the period September 1981 to September 1991, 130 were for simple, unresolved congenital nasolacrimal duct obstruction. Other indications for surgery included punctal agenesis, lacrimal fistula, post-traumatic and post-inflammatory canalicular obstruction. Of 177 children without canalicular pathology, 171 (96%) were relieved of symptoms with one operation, without canalicular intubation. Of 81 cases with canalicular disease, 55 of 70 (79%) who underwent DCR plus canalicular intubation, and 10 of 11 who underwent DCR plus Lester-Jones tube, were substantially improved with one operation. No child required peroperative or postoperative blood transfusion. Dacryocystorhinostomy in childhood, in experienced surgical hands, is a safe procedure, achieving relief of symptoms in most cases, particularly in the absence of canalicular disease.  相似文献   
4.
5.
The language-reading relationship in normal and reading-disabled children   总被引:1,自引:0,他引:1  
In this study, the word retrieval, phonological awareness, sentence completion, and narrative discourse processing skills of 93 reading-disabled and 93 normally achieving subjects from 8 to 14 years of age were compared. The subjects were matched for age, sex, and neighborhood. Results revealed that the two groups differed significantly on the time and accuracy of word retrieval, their ability to produce a syntactically appropriate structure in a sentence completion task, their retelling of stories that had been read to them, their answers to questions about the stories, and their inferences. Further analysis revealed that the variance in the younger reading-disabled children's reading comprehension scores was best accounted for by their performance on the sentence completion and word retrieval measures; the inferencing skills of the older reading-disabled children best accounted for the variance in their reading comprehension. By contrast, the younger normally achieving children's reading comprehension scores were best accounted for by their sentence completion, the proportion of the stories that they retold, and word retrieval scores. The proportion of stories retold and the phonological awareness score of the older normally achieving children best accounted for the variance in their reading scores. These findings suggest that the oral language skills of normally achieving and reading-disabled children may relate differently to their reading comprehension at different age levels.  相似文献   
6.
7.
Oral glucocorticoids are widely used to treat exacerbations of asthma and COPD. A role for their use in treating exacerbations in Cystic Fibrosis (CF) is not proven. We describe the current practice, amongst UK adult CF physicians, of oral glucocorticoid use as an adjuvant to intravenous (IV) antibiotic treatment during CF pulmonary exacerbation (P EX). The survey also examined whether physicians thought a randomised controlled trial (RCT) was necessary and their willingness to participate patients in such a trial. Eighty one percent of physicians replied. All of them used corticosteroids with P EX. Most physicians supported the need for a RCT and would be willing to enroll consenting patients in the trial. This survey highlighted the need for a RCT which would examine the role of adjuvant corticosteroids to IV antibiotics in CF P EX.  相似文献   
8.
OBJECTIVE: The indications for pre-operative radiotherapy in rectal cancer are still unclear with the exception of T4 tumours. The aim of this study was to assess local and overall recurrence in patients with T1-T3 rectal cancers undergoing total mesorectal excision (TME). METHODS: Prospective data was collected from 150 patients with rectal cancer treated in one surgical centre between July 1997 and July 2002. One hundred and twenty-nine primary resections were carried of which 102 were with curative intent. Seventy-nine patients with T1-T3 tumours were included in the analysis. Nine had local resections and 70 underwent TME; 19 of the 70 patients were node positive and 51 were node negative. RESULTS: At a median follow-up of 37 months (range 19-79 months) there were 3 (4.3%) isolated local recurrences. One node positive patient developed isolated local recurrence compared with 2 node negative patients. The node positive patient died from a myocardial infarction while the two node negative patients died as a consequence of local recurrence. Three (4.3%) of 70 patients developed systemic relapse all of whom were node positive. The cancer specific mortality rate over the same follow-up period was 3/19 for node positive patients and 2/51 for node negative patients. Of 9 patients who had local resections, none developed local recurrence or systemic relapse. CONCLUSIONS: With TME the rate of local recurrence in T1-T3 tumours is low. Our results do not support the use of pre-operative radiotherapy for these patients.  相似文献   
9.
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