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   1245篇
  免费   185篇
  国内免费   1篇
耳鼻咽喉   15篇
儿科学   31篇
妇产科学   64篇
基础医学   225篇
口腔科学   65篇
临床医学   132篇
内科学   244篇
皮肤病学   6篇
神经病学   174篇
特种医学   16篇
外科学   113篇
综合类   36篇
预防医学   143篇
眼科学   6篇
药学   143篇
肿瘤学   18篇
  2021年   8篇
  2019年   24篇
  2018年   29篇
  2017年   15篇
  2016年   14篇
  2015年   13篇
  2014年   24篇
  2013年   50篇
  2012年   53篇
  2011年   56篇
  2010年   33篇
  2009年   39篇
  2008年   51篇
  2007年   54篇
  2006年   54篇
  2005年   45篇
  2004年   62篇
  2003年   50篇
  2002年   47篇
  2001年   42篇
  2000年   67篇
  1999年   51篇
  1998年   18篇
  1997年   19篇
  1996年   25篇
  1995年   23篇
  1994年   14篇
  1993年   14篇
  1992年   30篇
  1991年   35篇
  1990年   30篇
  1989年   23篇
  1988年   18篇
  1987年   28篇
  1986年   31篇
  1985年   20篇
  1984年   17篇
  1983年   14篇
  1982年   20篇
  1981年   14篇
  1980年   14篇
  1979年   11篇
  1978年   11篇
  1977年   7篇
  1976年   10篇
  1974年   8篇
  1972年   10篇
  1971年   12篇
  1969年   10篇
  1966年   9篇
排序方式: 共有1431条查询结果,搜索用时 15 毫秒
81.
During a community echovirus type 33 outbreak, the virus was detected in the feces and cerebrospinal fluid of a 3-year-old boy with right arm weakness that followed a mild nonspecific febrile illness. This is the first time an association between echovirus type 33 infection and acute flaccid paralysis has been reported.  相似文献   
82.
83.
Mannan-binding lectin and its role in innate immunity   总被引:16,自引:0,他引:16  
Mannan-binding lectin (MBL) is a plasma collectin (C-type lectin with a collagen-like domain) and is considered an important component of innate immunity. Circulating MBL is genetically determined for the major part, but plasma concentration is also markedly influenced by nongenetic factors. The carbohydrate-binding ability of MBL can be inhibited by simple sugars like mannose, fucose and N-acetylglucosamine, but its greatest avidity appears to be for repeating mannose-based structural patterns typical of microbial surfaces. By this means, MBL can bind to a wide variety of bacteria and other microbes, neutralizing them and/or opsonizing them by activating complement using the recently discovered lectin pathway of complement activation. Individual humans differ 1000-fold in MBL concentration, and individuals with low circulating MBL appear to be more vulnerable to infections in a number of clinical settings, especially when combined with secondary immune deficiency. The best evidence that MBL deficiency or insufficiency is physiologically relevant comes from a rapidly expanding literature of clinical studies. MBL insufficiency appears to be a significant risk factor for infections in infants, and for individuals of any age undergoing chemotherapy or post-transplant immunosuppression. Moreover, MBL appears to have a significant influence on the course of certain chronic diseases like rheumatoid arthritis and cystic fibrosis. Replacement therapy with a plasma-derived product is safe and seems promising, while recombinant MBL provides hope for large-scale therapeutic applications. Randomized clinical trials of MBL therapy, which are now on the horizon, should provide unambiguous evidence for the physiological significance of MBL in innate immunity.  相似文献   
84.
This study was conducted to examine the volume of the basal ganglia in individuals with autism and to evaluate whether performance on specific motor tasks correlated with the volume of these structures. Volumetric measurements of the caudate nucleus and putamen were obtained from magnetic resonance images (MRI) of 40 non-mentally retarded individuals with autism and 41 healthy controls. Motor performance was assessed in these subjects by using the Finger Tapping Test, the Grooved Pegboard Test, and the measurement of Grip Strength. No volumetric differences of the basal ganglia were found between the two groups after adjusting for brain volume. The autistic subjects' performance was slower on the Grooved Pegboard Test and weaker on Grip Strength. Our findings suggest that the motor deficits observed in autism may not be related to structural abnormalities of the basal ganglia, and other brain regions, such as the cerebellum and the frontal lobe, may be involved in the pathophysiology of motor disturbances in autism.  相似文献   
85.
86.
87.
In response to the Balanced Budget Act (BBA) of 1997, the Center for Medicare & Medicaid Services (CMS) initiated a massive information and education campaign to promote effective health plan decision-making. Early results suggest that the pilot version of the Medicare & You handbook and other new Medicare informational materials were viewed favorably overall. Despite their limitations, most beneficiaries found the information useful. The longer, more comprehensive materials were not perceived to be more useful than the shorter, less complicated version. Additional research is needed to determine which subgroups of beneficiaries may need more and, possibly less, information.  相似文献   
88.
89.
Certain sulphur-containing amino acids are putative excitatory transmitters in the mammalian central nervous system. The quantification and a partial regional analysis of these compounds in the rat brain is presented. Our findings show that (S)-(+)-homocysteate, determined for the first time, is the most concentrated of those sulphonic and sulphinic amino acids assayed here.  相似文献   
90.
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