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   6975篇
  免费   481篇
  国内免费   11篇
耳鼻咽喉   86篇
儿科学   203篇
妇产科学   220篇
基础医学   816篇
口腔科学   197篇
临床医学   834篇
内科学   1462篇
皮肤病学   146篇
神经病学   622篇
特种医学   562篇
外科学   824篇
综合类   140篇
一般理论   5篇
预防医学   493篇
眼科学   143篇
药学   442篇
中国医学   12篇
肿瘤学   260篇
  2021年   71篇
  2020年   68篇
  2019年   107篇
  2018年   130篇
  2017年   110篇
  2016年   108篇
  2015年   98篇
  2014年   162篇
  2013年   221篇
  2012年   283篇
  2011年   340篇
  2010年   205篇
  2009年   177篇
  2008年   300篇
  2007年   279篇
  2006年   316篇
  2005年   311篇
  2004年   279篇
  2003年   247篇
  2002年   250篇
  2001年   225篇
  2000年   232篇
  1999年   180篇
  1998年   96篇
  1997年   114篇
  1996年   114篇
  1995年   89篇
  1994年   92篇
  1993年   70篇
  1992年   121篇
  1991年   148篇
  1990年   145篇
  1989年   155篇
  1988年   141篇
  1987年   142篇
  1986年   150篇
  1985年   132篇
  1984年   95篇
  1983年   95篇
  1982年   65篇
  1981年   54篇
  1980年   58篇
  1979年   61篇
  1978年   52篇
  1977年   55篇
  1976年   38篇
  1975年   49篇
  1974年   43篇
  1973年   40篇
  1967年   38篇
排序方式: 共有7467条查询结果,搜索用时 406 毫秒
1.
2.
3.
Biopsies from the diseased bones of patients with familial expansile osteolysis (FEO) were examined by light and electron microscopy. Focal concentrations of multinuclear osteoclasts were present, and these contained viral-like microcylindrical inclusions which appeared exclusive to their nuclei. No consistent relationship was found between osteoclast size and the number of osteoclast nuclei containing microcylindrical inclusions. Quantitative histomorphometry showed evidence of increased bone remodelling with high bone cell densities and a decrease of the reversal period in bone remodelling. The lesions contained prominent woven bone and fibrovascular tissue, together with mononuclear cells and adipocytes. Little bone was found in the most radiolucent lesions, which were almost totally occupied by adipocytes and fibrovascular tissue. Serology did not reveal any significant differences between the viral antibody titres of patients and their age- and sex-matched controls. The present study suggests that intranuclear viral-like microcylindrical inclusions of osteoclasts are not a specific feature of Paget's disease, and are found in other disorders of osteoclast function, including pycnodysostosis, osteopetrosis, giant cell tumours, and familial expansile osteolysis.  相似文献   
4.
Aims: On the Edge is a mental health education programme designed to support early intervention by increasing knowledge and understanding of early psychosis, reducing the stigma associated with mental health issues and improving awareness of avenues of help. The target audience was young people aged 14–22 years in schools and colleges. Methods: An interactive drama programme was developed through collaborative working across psychiatry, applied drama and those with direct experience of psychosis. A national tour engaged 2500 students in 71 performances that took place in 51 schools and colleges. The programme was evaluated against its aims with data collected both during and after the tour. Results: Quantitative and qualitative evaluation found significant gains with respect to all three aims. Thirty‐one schools developed supportive links with local mental health services. Conclusions: This programme shows the value and effectiveness of delivering health education on early psychosis through the medium of applied drama, and offers a model for a programme that can be incorporated into early intervention services. Lessons learned through delivering this programme are a valuable contribution towards future developments of mental health education programmes for schools.  相似文献   
5.
All nine exons of the ADH2(3) allele, which encodes the human alcohol dehydrogenase beta 3 subunit, have been cloned and sequenced. Comparison of this sequence to the ADH2(1) nucleotide sequence revealed only a single difference that results in an amino acid change, thus proving that the significant kinetic differences between these two isozymes is due to the Cys for Arg substitution at position 369. There are also two silent polymorphisms, and two changes in noncoding regions.  相似文献   
6.
Progressive peripheral cone dysfunction   总被引:1,自引:0,他引:1  
A 22-year-old man had a three-year history of progressive day blindness, most notably peripherally, and denied difficulty with central vision or color vision. Visual function studies demonstrated a diffuse dysfunction of the photopic system and normal scotopic function. The central cone function, however, was essentially normal. Visual acuity was 20/20 in each eye, results on AO-HRR and Ishihara color plate testing were normal, color naming visual fields demonstrated color discrimination in the central 10 degrees, and foveal adaptation was normal.  相似文献   
7.
8.
Conventional risk factors have very low predictive power in identifying haemodialysis patients at high risk of vascular accidents. A role for apolipoprotein E isotypes was looked for in a small, but rigorously defined, cohort of longterm haemodialysis patients. In individuals with high vascular risk, as identified by higher common carotid intima/media thickness, we found an excess of apolipoprotein E4 alleles. This preliminary result requires confirmation in large patient cohorts.   相似文献   
9.
10.
Temporal modulation transfer functions (MTF's) were recorded from the macula of nine normal subjects using focal electroretinography (FERG). An array of light emitting diodes (LED's) was used to experimentally manipulate stimulus temporal frequency, modulation depth, and mean luminance values. Two techniques were used to derive FERG modulation thresholds at several temporal frequencies: conventional averaging with extrapolation to a criterion amplitude, and a swept stimulus lock-in retrieval method. These two methods produced comparable results. The electrophysiologically derived MTF's were similar in shape to those obtained psychophysically. Six patients with retinal disease were also examined; all patients showed sensitivity losses which were most marked at the higher frequencies. Such losses tended to be greater in patients with poorer visual acuity.  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