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   208650篇
  免费   2927篇
  国内免费   107篇
耳鼻咽喉   1554篇
儿科学   8487篇
妇产科学   3654篇
基础医学   20831篇
口腔科学   2297篇
临床医学   14701篇
内科学   37517篇
皮肤病学   1485篇
神经病学   18195篇
特种医学   9645篇
外科学   33410篇
综合类   3617篇
一般理论   15篇
预防医学   20038篇
眼科学   4230篇
药学   12757篇
中国医学   900篇
肿瘤学   18351篇
  2023年   211篇
  2022年   544篇
  2021年   1165篇
  2020年   643篇
  2019年   876篇
  2018年   22756篇
  2017年   17897篇
  2016年   20273篇
  2015年   1853篇
  2014年   2110篇
  2013年   2456篇
  2012年   9214篇
  2011年   23203篇
  2010年   19987篇
  2009年   12593篇
  2008年   21077篇
  2007年   23228篇
  2006年   2226篇
  2005年   3461篇
  2004年   4673篇
  2003年   5436篇
  2002年   3413篇
  2001年   1075篇
  2000年   1262篇
  1999年   877篇
  1998年   500篇
  1997年   407篇
  1996年   306篇
  1995年   312篇
  1994年   269篇
  1993年   205篇
  1992年   532篇
  1991年   485篇
  1990年   548篇
  1989年   468篇
  1988年   408篇
  1987年   393篇
  1986年   369篇
  1985年   351篇
  1984年   280篇
  1983年   239篇
  1982年   163篇
  1979年   232篇
  1978年   156篇
  1977年   183篇
  1975年   176篇
  1974年   201篇
  1973年   183篇
  1972年   173篇
  1971年   161篇
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
101.
102.
Objective This study aims to question the generally accepted cerebrospinal fluid (CSF) bulk flow theory suggesting that the CSF is exclusively absorbed by the arachnoid villi and that the cause of hydrocephalus is a CSF absorption deficit. In addition, this study aims to briefly describe the new hydrodynamic concept of hydrocephalus and the rationale for endoscopic third ventriculostomy (ETV) in communicating hydrocephalus. Critique The bulk flow theory has proven incapable of explaining the pivotal mechanisms behind communicating hydrocephalus. Thus, the theory is unable to explain why the ventricles enlarge, why the CSF pressure remains normal and why some patients improve after ETV. Hydrodynamic concept of hydrocephalus Communicating hydrocephalus is caused by decreased intracranial compliance increasing the systolic pressure transmission into the brain parenchyma. The increased systolic pressure in the brain distends the brain towards the skull and simultaneously compresses the periventricular region of the brain against the ventricles. The final result is the predominant enlargement of the ventricles and narrowing of the subarachnoid space. The ETV reduces the increased systolic pressure in the brain simply by venting ventricular CSF through the stoma. The patent aqueduct in communicating hydrocephalus is too narrow to vent the CSF sufficiently.  相似文献   
103.
Abstract Objective: To define the diagnostic accuracy of clinical examination in patients with impaired consciousness or endotracheal intubation to detect pelvic ring fractures and to identify those with severe bleeding. Methods: Included in this prospective data collection with retrolective data analysis were a consecutive series of blunt trauma victims with either a Glasgow Coma Scale ≤ 13 or tracheal intubation. Clinical examination comprised testing for stability of the iliac wings. Results: From 784 subjects (injury severity score 23.3 ± 17.4) 93 patients (11.9%) were found to have a pelvic ring fracture. Clinical instability of the pelvic ring was found in 42 patients. There was only one false positive. Fifty-two fractures could not be identified by clinical examination, including nine fractures (17%) that required surgical fracture stabilization (sensitivity of clinical examination 44.1%). Seventeen fractures (18.3%) were associated with a blood loss larger than 20% of circulating blood volume. Sixteen of those were identified by clinical instability of the pelvic ring (sensitivity 94.1%, specificity 97.0%, positive predictive value 38.1%, negative predictive value 99.9%). Conclusions: Clinical examination for stability of the pelvis in this selected group of patients missed a significant number of pelvic ring fractures including fractures that require surgical stabilization. The finding of a clinically unstable identifies most of the patients with the pelvic ring fracture being a major source of bleeding. A stable pelvis makes pelvic ring fracture as being the source of bleeding quite unlikely.  相似文献   
104.
Serum LH, FSH and testosterone were quantitated in 9 patients with pure motor stroke within 24-48 h of its reported onset. High circulating LH with normal or low testosterone was noted in 8 of them. In response to an intravenous bolus of GnRH, the LH responses were exaggerated in all, but the FSH responses in 7 of them were comparable to those in eugonadal age matched controls. The rise in testosterone following 2000U hCG daily for 3 consecutive days was insignificant in the patients group compared to the controls. The data suggest normally operative pituitary testicular feed-back but decreased Leydig cell response in pure motor stroke.  相似文献   
105.

Background  

Reports on childhood cancer survivors estimated cumulative probability of developing secondary neoplasms vary from 3,3% to 25% at 25 years from diagnosis, and the risk of developing another cancer to several times greater than in the general population.  相似文献   
106.
107.
108.

Background  

It is well known that physicians' night-call duty may cause impaired performance and adverse effects on subjective health, but there is limited knowledge about effects on sleep duration and recovery time. In recent years occupational stress and impaired well-being among anaesthesiologists have been frequently reported for in the scientific literature. Given their main focus on handling patients with life-threatening conditions, when on call, one might expect sleep and recovery to be negatively affected by work, especially in this specialist group. The aim of the present study was to examine whether a 16-hour night-call schedule allowed for sufficient recovery in anaesthesiologists compared with other physician specialists handling less life-threatening conditions, when on call.  相似文献   
109.
Associations between street connectivity and active transportation   总被引:1,自引:0,他引:1  

Background  

Past studies of associations between measures of the built environment, particularly street connectivity, and active transportation (AT) or leisure walking/bicycling have largely failed to account for spatial autocorrelation of connectivity variables and have seldom examined both the propensity for AT and its duration in a coherent fashion. Such efforts could improve our understanding of the spatial and behavioral aspects of AT. We analyzed spatially identified data from Los Angeles and San Diego Counties collected as part of the 2001 California Health Interview Survey.  相似文献   
110.

Objective  

To test the effects of the use of a collapsible, portable chair (chair B), as opposed to a ‘standard’ chair (chair A), on the outcome of the timed “Up and Go” (TUG) test.  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