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   17287篇
  免费   1517篇
  国内免费   47篇
耳鼻咽喉   123篇
儿科学   416篇
妇产科学   652篇
基础医学   2568篇
口腔科学   266篇
临床医学   2434篇
内科学   3603篇
皮肤病学   331篇
神经病学   1453篇
特种医学   757篇
外国民族医学   4篇
外科学   2299篇
综合类   226篇
一般理论   4篇
预防医学   1253篇
眼科学   263篇
药学   972篇
中国医学   8篇
肿瘤学   1219篇
  2021年   174篇
  2020年   147篇
  2019年   231篇
  2018年   313篇
  2017年   261篇
  2016年   249篇
  2015年   341篇
  2014年   441篇
  2013年   585篇
  2012年   722篇
  2011年   749篇
  2010年   475篇
  2009年   516篇
  2008年   733篇
  2007年   728篇
  2006年   743篇
  2005年   651篇
  2004年   648篇
  2003年   659篇
  2002年   624篇
  2001年   585篇
  2000年   608篇
  1999年   500篇
  1998年   254篇
  1997年   246篇
  1996年   236篇
  1995年   213篇
  1994年   194篇
  1993年   155篇
  1992年   391篇
  1991年   366篇
  1990年   370篇
  1989年   355篇
  1988年   363篇
  1987年   327篇
  1986年   344篇
  1985年   311篇
  1984年   224篇
  1983年   182篇
  1982年   123篇
  1979年   167篇
  1978年   174篇
  1977年   150篇
  1976年   120篇
  1975年   167篇
  1974年   179篇
  1973年   132篇
  1972年   137篇
  1971年   139篇
  1970年   121篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
A growing body of evidence has suggested that the imbalance of epigenetic markers and oxidative stress appears to be involved in the pathophysiology and progression of stroke. Thus, strategies that modulate these biomarkers might be considered targets for neuroprotection and novel therapeutic opportunities for these patients. Physical exercise has been reported to induce changes in these epigenetic markers and improve clinical outcomes in different populations. However, little is reported on this in post-stroke patients. The purpose of this study was to investigate the effect of a single exercise session with Walk Aide functional electrical stimulation(FES) on cognitive performance, clinical functional parameters, oxidative stress and epigenetic modulation in post-stroke individuals. In this crossover design study, 12 post-stroke individuals aged 54–72 years of either sexes were included and subjected to a single session of exercise(45 minutes) without Walk Aide functional electrical stimulation(EXE alone group), followed by another single session of exercise(45 minutes) with Walk Aide functional electrical stimulation(EXE + FES group). The clinical functional outcome measures, cognitive performance and blood collections for biomarker measurements were assessed pre-and post-intervention. After intervention, higher Berg Balance Scale scores were obtained in the EXE + FES group than in the EXE alone group. There was no significant difference in the Timed Up and Go test results post-intervention between EXE alone and EXE + FES groups. After intervention, a better cognitive performance was found in both groups compared with before the intervention. After intervention, the Timed Up and Go test scores were higher in the EXE + FES group than in the EXE alone group. In addition, the intervention induced lower levels of lipid peroxidation. After intervention, carbonyl level was lower, superoxide dismutase activity and superoxide dismutase/catalase activity ratio were higher in the EXE + FES group, compared with the EXE group alone. In each group, both histone deacetylase(HDAC2) and histone acetyltransferase activities were increased after intervention compared with before the intervention. These findings suggest that a single exercise session with Walk Aide FES is more effective on balance ability and cognitive performance compared with conventional exercise alone in post-stroke patients. This is likely to be related to the regulation of oxidative stress markers. The present study was approved by the Research Ethics Committee of the Methodist University Center-IPA(approval No. 2.423.376) on December 7, 2017 and registered in the Brazilian Registry of Clinical Trials—Re BEC(RBR-9 phj2 q) on February 11, 2019.  相似文献   
2.
3.
4.
Critical airway incidents in children are a frequent problem in pediatric anesthesia and remain a significant cause of morbidity and mortality. Young children are at particular risk in the perioperative period. Delayed management of airway obstruction can quickly lead to serious complications due to the short apnea tolerance in children. A simple, time critical, and pediatric‐specific airway management approach combined with dedicated teaching, training, and frequent practice will help to reduce airway‐related pediatric morbidity and mortality. There is currently no pediatric‐specific universal framework available to guide practice. Current algorithms are modifications of adult approaches which are often inappropriate because of differences in age‐related anatomy, physiology, and neurodevelopment. A universal and pragmatic approach is required to achieve acceptance across diverse pediatric clinicians, societies, and groups. Such a framework will also help to establish minimum standards for pediatric airway equipment, personnel, and medications whenever pediatric airway management is required.  相似文献   
5.
6.
The wrist can be considered a 2 degrees‐of‐freedom joint with all movements reflecting the combination of flexion–extension and radial–ulnar deviation. Wrist motions are accomplished by the kinematic reduction of the 42 degrees‐of‐freedom of the individual carpal bones. While previous studies have demonstrated the minimal motion of the scaphoid and lunate as the wrist moves along the dart‐thrower's path or small relative motion between hamate‐capitate‐trapezoid, an understanding of the kinematics of the complete carpus across all wrist motions remains lacking. To address this, we assembled an open‐source database of in vivo carpal motions and developed mathematical models of the carpal kinematics as a function of wrist motion. Quadratic surfaces were trained for each of the 42‐carpal bone degrees‐of‐freedom and the goodness of fits were evaluated. Using the models, paths of wrist motion that generated minimal carpal rotations or translations were determined. Model predictions were best for flexion–extension, radial–ulnar deviation, and volar–dorsal translations for all carpal bones with R 2 > 0.8, while the estimates were least effective for supination‐pronation with R 2 < 0.6. The wrist path of motion's analysis indicated that the distal row of carpal bones moves rigidly together (<3° motion), along the anatomical axis of wrist motion, while the bones in the proximal row undergo minimal motion when the wrist moves in a path oblique to the main axes. The open‐source dataset along with its graphical user interface and mathematical models should facilitate clinical visualization and enable new studies of carpal kinematics and function. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2661–2670, 2019  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