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   627篇
  免费   43篇
  国内免费   8篇
儿科学   51篇
妇产科学   3篇
基础医学   63篇
口腔科学   12篇
临床医学   81篇
内科学   102篇
皮肤病学   3篇
神经病学   8篇
特种医学   141篇
外科学   62篇
综合类   8篇
预防医学   28篇
眼科学   5篇
药学   27篇
中国医学   2篇
肿瘤学   82篇
  2023年   1篇
  2022年   2篇
  2021年   4篇
  2020年   5篇
  2019年   4篇
  2018年   7篇
  2017年   3篇
  2016年   5篇
  2015年   9篇
  2014年   8篇
  2013年   14篇
  2012年   11篇
  2011年   12篇
  2010年   12篇
  2009年   15篇
  2008年   16篇
  2007年   16篇
  2006年   19篇
  2005年   21篇
  2004年   11篇
  2003年   17篇
  2002年   13篇
  2001年   12篇
  2000年   11篇
  1999年   11篇
  1998年   39篇
  1997年   59篇
  1996年   40篇
  1995年   33篇
  1994年   34篇
  1993年   25篇
  1992年   12篇
  1991年   10篇
  1990年   6篇
  1989年   19篇
  1988年   20篇
  1987年   18篇
  1986年   21篇
  1985年   20篇
  1984年   9篇
  1983年   6篇
  1982年   11篇
  1981年   6篇
  1980年   8篇
  1978年   6篇
  1977年   8篇
  1976年   4篇
  1975年   5篇
排序方式: 共有678条查询结果,搜索用时 15 毫秒
1.
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   
2.
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   
3.
4.
5.
Factors influencing women to undergo screening mammography   总被引:2,自引:0,他引:2  
  相似文献   
6.
AIMS: The degradation of the extracellular matrix is intrinsic to the invasion and progression of cancer. Matrix metalloproteinase (MMP)-2 and -9 and their natural inhibitors are involved in this process. The study aims to investigate if plasma MMP-2, -9 and tissue inhibitor of metalloproteinase-1 (TIMP-1) can be useful markers in the diagnosis and prognosis of colorectal cancer (CRC) metastatic liver disease. METHODS: Fifty-seven patients undergoing liver metastasis operation were followed prospectively. ProMMP-2, -9 and TIMP-1 plasma levels were determined by zymography and ELISA, before and after the resection of liver metastases. Data were compared with those of healthy controls (n=51) and primary CRC patients (n=94). The diagnostic and prognostic potential was investigated with ROC-curves and Kaplan-Meier survival analysis. RESULTS: Plasma proMMP-2 levels were lower (P<0.001), and TIMP-1 levels higher (P<0.001) in CRC metastatic liver disease than in healthy controls. If compared to those in primary CRC patients, no differences were found. In ROC-curves, the area under the curve was 0.48 and 0.61 for proMMP-2 and -9, respectively. Plasma proMMP-2, -9 and TIMP-1 levels were unsuitable to predict survival. In both diagnostic and prognostic examinations, CEA proved to be a better marker. In the postoperative follow-up, protracted low levels of proMMP-2 seemed related to disease recurrence. CONCLUSION: The preoperative plasma proMMP-2, -9 and TIMP-1 levels have no potential value as diagnostic or prognostic markers in CRC liver metastatic disease.  相似文献   
7.
8.
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