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   14185篇
  免费   900篇
  国内免费   61篇
耳鼻咽喉   244篇
儿科学   223篇
妇产科学   239篇
基础医学   2078篇
口腔科学   1448篇
临床医学   1129篇
内科学   3182篇
皮肤病学   335篇
神经病学   974篇
特种医学   267篇
外科学   1722篇
综合类   51篇
一般理论   6篇
预防医学   1456篇
眼科学   174篇
药学   1042篇
中国医学   168篇
肿瘤学   408篇
  2023年   155篇
  2022年   278篇
  2021年   532篇
  2020年   368篇
  2019年   468篇
  2018年   586篇
  2017年   386篇
  2016年   426篇
  2015年   493篇
  2014年   638篇
  2013年   811篇
  2012年   1131篇
  2011年   1345篇
  2010年   674篇
  2009年   526篇
  2008年   817篇
  2007年   829篇
  2006年   704篇
  2005年   635篇
  2004年   516篇
  2003年   418篇
  2002年   393篇
  2001年   261篇
  2000年   279篇
  1999年   228篇
  1998年   57篇
  1997年   53篇
  1996年   34篇
  1995年   36篇
  1994年   51篇
  1993年   34篇
  1992年   106篇
  1991年   71篇
  1990年   82篇
  1989年   73篇
  1988年   52篇
  1987年   52篇
  1986年   48篇
  1985年   46篇
  1984年   32篇
  1983年   27篇
  1980年   25篇
  1979年   25篇
  1978年   29篇
  1974年   26篇
  1973年   26篇
  1972年   22篇
  1971年   23篇
  1970年   22篇
  1967年   22篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
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   
13.
14.
15.
16.
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   
17.
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   
18.

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   
19.
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