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   3136篇
  免费   370篇
  国内免费   42篇
耳鼻咽喉   14篇
儿科学   150篇
妇产科学   69篇
基础医学   466篇
口腔科学   49篇
临床医学   314篇
内科学   1011篇
皮肤病学   21篇
神经病学   182篇
特种医学   265篇
外科学   359篇
综合类   48篇
一般理论   8篇
预防医学   318篇
眼科学   29篇
药学   161篇
肿瘤学   84篇
  2022年   19篇
  2021年   33篇
  2020年   25篇
  2019年   41篇
  2018年   41篇
  2017年   41篇
  2016年   38篇
  2015年   43篇
  2014年   60篇
  2013年   76篇
  2012年   164篇
  2011年   168篇
  2010年   77篇
  2009年   88篇
  2008年   140篇
  2007年   179篇
  2006年   135篇
  2005年   145篇
  2004年   133篇
  2003年   124篇
  2002年   99篇
  2001年   113篇
  2000年   91篇
  1999年   105篇
  1998年   86篇
  1997年   70篇
  1996年   57篇
  1995年   54篇
  1994年   37篇
  1993年   60篇
  1992年   40篇
  1991年   67篇
  1990年   35篇
  1989年   64篇
  1988年   64篇
  1987年   60篇
  1986年   38篇
  1985年   44篇
  1984年   38篇
  1983年   32篇
  1982年   29篇
  1981年   33篇
  1980年   37篇
  1979年   20篇
  1978年   32篇
  1977年   22篇
  1976年   28篇
  1974年   33篇
  1973年   27篇
  1972年   21篇
排序方式: 共有3548条查询结果,搜索用时 15 毫秒
11.
12.
Normal and diseased isolated lungs: high-resolution CT   总被引:8,自引:0,他引:8  
  相似文献   
13.
A cross-sectional survey research design measured factors related to cigarette use among 2,212 senior high school students. Results showed 14.3% of the sample smoked cigarettes at least occasionally, with 5.3% reporting they were daily smokers. About 12.8% indicated they were ex-smokers. Males and females smoked at almost equal rates, and the percentage of 10th grade student smokers was slightly higher (16.4%) than the percentage of juniors and seniors who smoked. Approximately 22% of Hispanic students, 15% of Caucasian students, and 4.5% of African-American students reported smoking cigarettes at least occasionally. An initial regression analysis used 21 variables to predict cigarette smoking. A more parsimonious regression model (R2 = .28), using variables from the initial regression analysis with significance levels of .01 or less, indicated the most important predictors of cigarette use were ethnic group, attitude toward females who smoke, close friends' use of cigarettes, personal use of marijuana, best friend's use of cigarettes, personal use of alcohol, and school self-esteem. Implications for school health programs are addressed.  相似文献   
14.
Psychological outcomes of a pulmonary rehabilitation program   总被引:3,自引:0,他引:3  
This study assessed physiologic, psychological, and cognitive functioning in outpatients with COPD. Sixty-four subjects, 53 to 82 years of age, participated in the 30-day exercise rehabilitation program. The program consisted of exercise, education and psychosocial counselling. Participants were assessed prior to beginning the program and at the end of 30 days. Assessments at both times included physiologic functioning (bicycle ergometry testing, pulmonary function tests, 12-min walk), psychological well-being (anxiety, depression, psychiatric symptoms, perceived well-being) and an abbreviated neuropsychological test battery. Results indicate significant improvement in physical endurance and pulmonary function, significant reductions in symptoms of depression and anxiety, and improvement in measures of general well-being and neuropsychological functioning. The study suggests that exercise rehabilitation of older adults with COPD contributes not only to improvements in physical functioning and endurance, but also to enhanced cognitive functioning and psychological well-being.  相似文献   
15.
16.
Shiota  Y; Wilson  JG; Harjes  K; Zanjani  ED; Tavassoli  M 《Blood》1993,82(5):1436-1444
The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells. This protein, designated p37, could be surface-radiolabeled and thus appeared to be exposed on the cell membrane. An apparently identical 37- Kd protein was expressed by three stromal cell lines, by Swiss 3T3 fibroblastic cells, and by FDCP-1 and FDCP-2 progenitor cells. p37 was selectively adsorbed from membrane lysates by a variety of murine hematopoietic cells, including erythrocytes, but not by human erythrocytes. Binding of p37 to cells was calcium-dependent, and was not affected by inhibitors of the hematopoietic homing receptor or the cell-binding or heparin-binding functions of fibronectin. It is proposed that p37 may be a novel adhesive molecule expressed on the surface of a variety of hematopoietic cells that could participate in both homotypic and heterotypic interactions of stromal and progenitor cells.  相似文献   
17.
The authors analysed the clinical and radiological findings and the surgical management of 25 patients admitted for scoliosis classified as idiopathic at first presentation, but in fact associated with spinal cord and/or brain stem anomalies. Twenty patients had syringomyelia, 19 had Chiari malformation. Scoliosis was the only presenting symptom when all these patients were referred to the orthopaedic surgeon. On examination, five patients had normal neurological findings, while the others showed very mild neurological deficits. The diagnosis of syringomyelia and Chiari malformation was established by MRI, which is the best form of neuroradiological examination for discovering spinal abnormalities. Neurosurgical treatment is strongly recommended as the first step in the management of “pseudo” idiopathic scoliosis.  相似文献   
18.
19.
20.
This research was supported by a grant from The Foundation for Physical Therapy, Alexandria, VA. The purpose of this study was to determine the reliability of a quantitative measure of knee ligament laxity in vivo. The testing device simultaneously measures applied forces and resulting displacement at the knee through use of a multidimensional electrogoniometer, dynamometer, and a computer-assisted analysis system. Subjects were 30 females and 20 males, ranging in age from 18-32 years. Laxity tests were performed in the anterior/posterior (A/P) plane at 90 and 30 degrees of knee flexion, and the varus/valgus (V/V) plane at 20 and 0 degrees of knee flexion. Test-retest (N = 41) and intertester (N = 18) repeatability was assessed in all test positions by ANOVA and by coefficients of correlation and variability. No significant differences were found within testers for A/P or V/V tests 1 week apart at any angle tested. There were significant differences between testers for A/P and V/V tests. No significant differences were found between left and right sides, or between male/female values. Comparisons to other in vitro and in vivo studies are made. J Orthop Sports Phys Ther 1989;10(11):441-447.  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