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   1930篇
  免费   116篇
  国内免费   76篇
耳鼻咽喉   17篇
儿科学   136篇
妇产科学   36篇
基础医学   169篇
口腔科学   19篇
临床医学   232篇
内科学   413篇
皮肤病学   67篇
神经病学   56篇
特种医学   278篇
外科学   184篇
综合类   53篇
预防医学   145篇
眼科学   137篇
药学   108篇
中国医学   6篇
肿瘤学   66篇
  2023年   11篇
  2022年   9篇
  2021年   16篇
  2020年   21篇
  2019年   32篇
  2018年   29篇
  2017年   21篇
  2016年   27篇
  2015年   28篇
  2014年   38篇
  2013年   50篇
  2012年   68篇
  2011年   67篇
  2010年   54篇
  2009年   90篇
  2008年   70篇
  2007年   109篇
  2006年   67篇
  2005年   58篇
  2004年   49篇
  2003年   43篇
  2002年   41篇
  2001年   53篇
  2000年   65篇
  1999年   33篇
  1998年   100篇
  1997年   74篇
  1996年   68篇
  1995年   68篇
  1994年   50篇
  1993年   47篇
  1992年   44篇
  1991年   33篇
  1990年   44篇
  1989年   50篇
  1988年   51篇
  1987年   43篇
  1986年   34篇
  1985年   30篇
  1984年   26篇
  1983年   22篇
  1982年   23篇
  1981年   12篇
  1980年   17篇
  1979年   13篇
  1978年   12篇
  1977年   18篇
  1976年   19篇
  1975年   13篇
  1971年   8篇
排序方式: 共有2122条查询结果,搜索用时 15 毫秒
101.
102.
103.
PURPOSE: To evaluate surveillance methods in a pilot epidemiological study of contact lens related microbial keratitis (MK) cases identified by ophthalmic practitioners in Australia and New Zealand between May and August 2003 inclusive. METHODS: Twelve ophthalmologists and 55 optometrists from rural and metropolitan locations were sent a study information pack with postal reporting forms. After 2 months, practitioners were emailed a link to a website for Internet reporting. After 4 months, practitioners were prompted by email and then by telephone if a response was not received. Passive response rates were the rate of returns after posting information and emailing the website link. Active response rates included personalized email and telephone follow-up. RESULTS: Ten cases of MK were identified by optometrists and five by ophthalmologists. The passive response rates were 79% and 58% for the first and second reporting periods, respectively. There was a lower response rate in the second reporting period compared to the first (P = 0.02). With active surveillance the response rate increased to 97% and 96%. A large proportion of optometrists (62%) and ophthalmologists (55%) used the website for at least one reporting period. Internet reporting was used by all New Zealand practitioners (5/5). CONCLUSIONS: A surveillance study to estimate the incidence of contact lens related MK in Australia and New Zealand is feasible and acceptable. Internet-based reporting offers a reliable, rapid and cost-effective means of running a large scale, international surveillance study. Active surveillance methods are necessary to enhance reporting rates.  相似文献   
104.
105.
106.
107.
108.
Sanfilippo B syndrome is caused by a deficiency of alpha-N- acetylglucosaminidase, a lysosomal enzyme involved in the degradation of heparan sulphate. Accumulation of the substrate in lysosomes results in degeneration of the central nervous system with progressive dementia often combined with hyperactivity and aggressive behaviour. In order to clone the deficient gene, we purified the enzyme from human placenta and obtained amino acid sequence information. Alignment of one of the CNBr generated internal peptides to sequence from the database revealed the chromosomal location of the gene in the 5' upstream flanking region of the gene for 17-beta-hydroxysteroid-dehydrogenase at 17q21.1. The available DNA sequence was used to clone the cDNA coding for alpha-N- acetylglucosaminidase and analyse its gene structure. The gene is fully contained in the 5' upstream flanking region of the gene for 17-beta- hydroxysteroid-dehydrogenase and interrupted by five introns. The cDNA clone has a length of 2575 bp and encodes a protein of 743 amino acids. Chinese hamster ovary cells transfected with the cDNA construct show alpha-N-acetylglucosaminidase activity about 17-fold over background. This will allow correction studies with NAG deficient Sanfilippo B cell lines and facilitate the development of enzyme replacement therapy for these patients.   相似文献   
109.
Journal of Neurology - Sex-specific differences in ischemic stroke outcomes are prevalent. We sought to investigate sex differences in the determinants of reperfusion and functional outcomes after...  相似文献   
110.
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