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   2711篇
  免费   429篇
  国内免费   41篇
耳鼻咽喉   27篇
儿科学   130篇
妇产科学   27篇
基础医学   295篇
口腔科学   52篇
临床医学   420篇
内科学   796篇
皮肤病学   64篇
神经病学   307篇
特种医学   288篇
外科学   350篇
综合类   54篇
一般理论   1篇
预防医学   135篇
眼科学   17篇
药学   122篇
中国医学   1篇
肿瘤学   95篇
  2023年   53篇
  2022年   22篇
  2021年   43篇
  2020年   93篇
  2018年   94篇
  2017年   81篇
  2016年   79篇
  2015年   73篇
  2014年   101篇
  2013年   125篇
  2012年   69篇
  2011年   70篇
  2010年   92篇
  2009年   130篇
  2008年   87篇
  2007年   83篇
  2006年   90篇
  2005年   66篇
  2004年   58篇
  2003年   61篇
  2002年   40篇
  2001年   55篇
  2000年   38篇
  1999年   61篇
  1998年   101篇
  1997年   118篇
  1996年   91篇
  1995年   81篇
  1994年   58篇
  1993年   66篇
  1992年   61篇
  1991年   40篇
  1990年   62篇
  1989年   79篇
  1988年   62篇
  1987年   43篇
  1986年   43篇
  1985年   45篇
  1984年   35篇
  1983年   27篇
  1982年   33篇
  1981年   24篇
  1980年   25篇
  1979年   27篇
  1978年   29篇
  1977年   23篇
  1974年   22篇
  1973年   20篇
  1971年   21篇
  1969年   24篇
排序方式: 共有3181条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease.  相似文献   
15.
16.
A simple necropsy technique for the removal of the craniocervical junction was devised: a relatively small specimen comprising part of the clivus, the foramen magnum, and cervical vertebral canal is removed in one piece with the medulla and spinal cord inside, and examined systematically after fixation. This method, used in a series of patients with chronic craniocervical instability, allows both good clinicopathological correlations to be made and histological changes in the lower medulla or upper cervical cord segments to be related to sites of extrinsic compression.  相似文献   
17.
18.
19.
The cystic fibrosis (CF) transmembrane conductance regulator protein can transport bicarbonate and may therefore regulate airway surface (AS) pH. Disturbances of AS pH could contribute to the pathophysiology of CF lung disease. Five studies were carried out including the following: study 1) nasal pH measurements were made in 25 CF and 10 non-CF adults using an antimony pH probe. Mean nasal pH was significantly lower in the CF group. Nasal potential difference may have been a confounding factor; study 2) in a fresh cohort of CF and non-CF subjects, no significant difference was found between the two groups using a gold pH probe; study 3) simultaneous nasal pH measurements were made in 15 CF and 15 non-CF adults using both probes. In the CF group, there was a trend for the antimony probe to read lower than the gold probe. In the non-CF group, the antimony probe read higher. The pH difference noted in study 1 related to technical factors; study 4) the effect of acute changes in serum acid/base balance on nasal pH was assessed in five non-CF adults. Nasal pH was not altered by either acute respiratory acidosis or alkalosis; study 5) nasal and lower airway pH was measured in five CF and six non-CF children. No difference was found between the groups. There was a correlation between nasal and lower airway pH. The authors conclude that airway surface pH does not differ between cystic fibrosis and noncystic fibrosis subjects and therefore, cystic fibrosis transmembrane conductance regulator may not play a major role in airway surface pH in vivo.  相似文献   
20.
The present study represents a comprehensive retrospective review of endocarditis in a large district general hospital since the inception of a formalized policy involving collaborative management a decade ago. The principle was to involve a recognised team of cardiologists, specialists in infectious disease and microbiologists in the treatment of the disease from the moment of its diagnosis. The pattern of infection has not altered in terms of prevalent organisms and valves infected since the change in management policy. There has, however, been a significant decline in the mortality, from 34 to 24% for all patients with endocarditis. Amongst those referred for collaborative management, the mortality has fallen to 6%. The single greatest improvement is a reduction in the number of patients dying of heart failure, the number of patients developing systemic emboli or requiring prosthetic valve replacement remaining unchanged. The results indicate that early referral to, and treatment by, a multidisciplinary team can significantly reduce the mortality from bacterial endocarditis.  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