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   11815篇
  免费   751篇
  国内免费   96篇
耳鼻咽喉   191篇
儿科学   213篇
妇产科学   219篇
基础医学   1768篇
口腔科学   1053篇
临床医学   1020篇
内科学   2710篇
皮肤病学   259篇
神经病学   770篇
特种医学   316篇
外科学   1352篇
综合类   46篇
一般理论   5篇
预防医学   1182篇
眼科学   118篇
药学   921篇
  1篇
中国医学   146篇
肿瘤学   372篇
  2023年   133篇
  2022年   194篇
  2021年   453篇
  2020年   292篇
  2019年   385篇
  2018年   485篇
  2017年   329篇
  2016年   349篇
  2015年   410篇
  2014年   531篇
  2013年   696篇
  2012年   934篇
  2011年   1092篇
  2010年   524篇
  2009年   428篇
  2008年   647篇
  2007年   703篇
  2006年   586篇
  2005年   495篇
  2004年   396篇
  2003年   336篇
  2002年   339篇
  2001年   214篇
  2000年   218篇
  1999年   178篇
  1998年   88篇
  1997年   95篇
  1996年   77篇
  1995年   73篇
  1994年   67篇
  1993年   53篇
  1992年   90篇
  1991年   65篇
  1990年   67篇
  1989年   67篇
  1988年   61篇
  1987年   46篇
  1986年   42篇
  1985年   45篇
  1984年   27篇
  1983年   22篇
  1982年   17篇
  1980年   28篇
  1978年   26篇
  1977年   18篇
  1975年   21篇
  1973年   23篇
  1971年   21篇
  1970年   17篇
  1969年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Cecal intubation is a critical aspect of effective, complete colonoscopy. Difficult colonoscopy is most often considered as one in which it is challenging or impossible to reach the cecum. It may be a common occurrence due to patient and/or endoscopist factors. Incomplete colonoscopies should be avoided, since patients in this context present an important prevalence of lesions that escape examination. The approach to successful cecal intubation should depend on characterization of the problem as redundant colon or difficult sigmoid colon. Most patients with a prior incomplete colonoscopy can be colonoscoped successfully, if careful attention is paid to technique, using a variety of scopes, colonoscopy methods and additional equipment. Sufficient time should be allotted to make the attempt.  相似文献   
12.
13.
14.
15.
L1 disease is the most common genetic cause of congenital hydrocephalus. Mutations in the L1CAM gene are associated with an overlapping clinical spectrum of four X-linked neurological conditions, characterized by hydrocephalus, mental retardation, lower limb spasticity and adducted thumbs. Brain anomalies are frequently present in L1 disease. We describe these anomalies by reporting a case of a male newborn presenting with congenital hydrocephalus along with corpus callosum agenesis and enlargement of the massa intermedia. These findings, in association with the presence of clasped thumbs, raised the suspicion of L1 disease, which was confirmed by the detection of a mutation in the L1CAM gene. In cases of congenital hydrocephalus, recognition of the brain anomalies associated with L1 disease may contribute to pursuing the genetic analysis needed for the diagnosis and genetic counseling.  相似文献   
16.
The aim of the present study was to probe the structural integrity of insulin after being entrapped into chitosan/alginate nanoparticles produced by ionotropic polyelectrolyte pre-gelation. By manipulating the alginate:chitosan mass ratio and the pH during nanoparticle production, desired nanoparticles with a mean size of 850 (+/-88)nm and insulin association efficiency of 81 (+/-2)% were obtained. Insulin secondary structure was assessed by Fourier transform infrared (FTIR) and circular dichroism (CD) after entrapment into nanoparticles and after release from the particles under gastrointestinal simulated conditions. FTIR second-derivative spectra and area-overlap compared to an insulin standard confirmed that no significant conformational changes of insulin occurred in terms of alpha-helix and beta-sheet content. Far-UV-CD spectra corroborated the preservation of insulin structure during the nanoparticle production procedure. The presented nanoparticulate system is a promising carrier for insulin oral delivery since it preserves insulin structure and therefore also, potentially, its bioactivity.  相似文献   
17.

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   
18.
19.

Background  

Shoulder disorders are a common health problem in western societies. Several treatment protocols have been developed for the clinical management of persons with shoulder pain. However available evidence does not support any protocol as being superior over others. Systematic reviews provide some evidence that certain physical therapy interventions (i.e. supervised exercises and mobilisation) are effective in particular shoulder disorders (i.e. rotator cuff disorders, mixed shoulder disorders and adhesive capsulitis), but there is an ongoing need for high quality trials of physical therapy interventions. Usually, physical therapy consists of active exercises intended to strengthen the shoulder muscles as stabilizers of the glenohumeral joint or perform mobilisations to improve restricted mobility of the glenohumeral or adjacent joints (shoulder girdle). It is generally accepted that a-traumatic shoulder problems are the result of impingement of the subacromial structures, such as the bursa or rotator cuff tendons. Myofascial trigger points (MTrPs) in shoulder muscles may also lead to a complex of symptoms that are often seen in patients diagnosed with subacromial impingement or rotator cuff tendinopathy. Little is known about the treatment of MTrPs in patients with shoulder disorders.  相似文献   
20.
Accidental transmission of Chagas disease to man by blood transfusion is a serious problem in Latin America. This paper describes the testing of several naphthoquinones, some of which were active against blood trypomastigotes in vitro at 4 degrees C and might therefore warrant further study for preventing transmission of Chagas disease by blood transfusion.  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