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   106445篇
  免费   6535篇
  国内免费   451篇
耳鼻咽喉   1239篇
儿科学   2761篇
妇产科学   1976篇
基础医学   13295篇
口腔科学   1826篇
临床医学   11126篇
内科学   21470篇
皮肤病学   1464篇
神经病学   10625篇
特种医学   4071篇
外国民族医学   3篇
外科学   17130篇
综合类   1180篇
一般理论   135篇
预防医学   8756篇
眼科学   2175篇
药学   6749篇
中国医学   105篇
肿瘤学   7345篇
  2023年   578篇
  2022年   964篇
  2021年   2178篇
  2020年   1370篇
  2019年   2160篇
  2018年   2622篇
  2017年   1892篇
  2016年   2057篇
  2015年   2346篇
  2014年   3551篇
  2013年   4911篇
  2012年   7796篇
  2011年   8224篇
  2010年   4713篇
  2009年   4243篇
  2008年   7350篇
  2007年   7665篇
  2006年   7388篇
  2005年   7083篇
  2004年   6909篇
  2003年   6234篇
  2002年   5887篇
  2001年   1013篇
  2000年   716篇
  1999年   1069篇
  1998年   1268篇
  1997年   971篇
  1996年   816篇
  1995年   734篇
  1994年   632篇
  1993年   612篇
  1992年   617篇
  1991年   544篇
  1990年   454篇
  1989年   426篇
  1988年   404篇
  1987年   427篇
  1986年   367篇
  1985年   413篇
  1984年   417篇
  1983年   364篇
  1982年   402篇
  1981年   340篇
  1980年   280篇
  1979年   187篇
  1978年   197篇
  1977年   154篇
  1976年   130篇
  1974年   128篇
  1973年   140篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
BACKGROUND: A subgroup of children with obsessive-compulsive and tic disorders are proposed to have an infectious trigger. The purpose of this study was to investigate the relationship between group A streptococcal titers and symptom fluctuations in children with a clinical course resembling that described for pediatric autoimmune neuropsychiatric disorders associated with streptococcus. METHODS: Twenty-five children with obsessive-compulsive disorder and/or tic disorder were evaluated for neuropsychiatric severity and group A streptococcal antibody titers (streptolysin O, deoxyribonuclease B, and carbohydrate A) at 6-week intervals for > or = six consecutive evaluations (total visits=277). RESULTS: Children with large symptom fluctuations (n=15) were compared with children without dramatic fluctuations (n=10). Co-movements of obsessive-compulsive/tic severity and group A streptococcal antibodies were assessed. In subjects with large symptom changes, positive correlations were found between streptococcal titers and obsessive-compulsive severity rating changes (p=.0130). These subjects were also more likely to have elevated group A streptococcal titers during the majority of observations (p=.001). Tic symptom exacerbations occurred more often in the fall/winter months than spring/summer months (p=.03). CONCLUSIONS: Patients with marked obsessive-compulsive/tic symptom changes may be characterized by streptococcal titer elevations and exhibit evidence of seasonal tic exacerbations.  相似文献   
113.
114.
Major depressive disorder is a psychiatric disorder that encompasses a broad range of emotional, psychological, behavioral, and physical symptoms (Fava et al., 2004). The nurse in the hospital, office, school, or community setting can provide the essential elements of effective care for depression, including early detection by screening, medication teaching, depression education, teaching coping skills, and appropriate use of specialists and resources. Utilizing the nursing process, the nurse can provide comprehensive care to improve the depressed patient's physical and psychological well-being.  相似文献   
115.
116.
117.
118.
119.
The short-term albumin affinity and thrombo-resistance of a polyether polyurethane vascular graft have been improved. The method is based on the C18 alkylation of the polymer. Thrombus formation by a planimetric technique and albumin retention on wire-reinforced polyurethane tubes, both C18 alkylated and untreated, were measured in short-term (4-h) exposure at femoral arterial sites in the dog. 125I-Albumin was preabsorbed on tubes and then exposed to blood for successive 2-h periods. Albumin uptake on alkylated tubes prior to blood exposure and retention following 2 h of blood exposure were significantly greater than on controls. Following a fast desorption phase in blood, the remaining albumin was more slowly desorbed from alkylated than from control tubes. Reincubation with albumin and blood reexposure produced a similar tendency, suggesting blood conditioning does not reduce the albumin affinity-enhancing property of C18 alkylation in the short term. Blood-preconditioning experiments suggested endogenous albumin has a high affinity for the C18-alkylated surface. Scanning electron microscopic examination showed thrombus and platelet densities were higher on control than on alkylated surfaces. These results suggest in vivo albumin affinity is increased for C18-alkylated polyurethane, which may be linked to decreased thrombus formation on these surfaces.  相似文献   
120.

Background  

Lag screw cut-out failure following fixation of unstable intertrochanteric fractures in osteoporotic bone remains an unsolved challenge. This study tested if resistance to cut-out failure can be improved by using a dual lag screw implant in place of a single lag screw implant. Migration behavior and cut-out resistance of a single and a dual lag screw implant were comparatively evaluated in surrogate specimens using an established laboratory model of hip screw cut-out failure.  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