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   920124篇
  免费   65223篇
  国内免费   2358篇
耳鼻咽喉   12829篇
儿科学   29336篇
妇产科学   26801篇
基础医学   129369篇
口腔科学   25265篇
临床医学   77478篇
内科学   186735篇
皮肤病学   19154篇
神经病学   72969篇
特种医学   37173篇
外国民族医学   336篇
外科学   145226篇
综合类   19473篇
一般理论   260篇
预防医学   67196篇
眼科学   20461篇
药学   65316篇
中国医学   1842篇
肿瘤学   50486篇
  2018年   9416篇
  2017年   7437篇
  2016年   7935篇
  2015年   9040篇
  2014年   12802篇
  2013年   19890篇
  2012年   26658篇
  2011年   28261篇
  2010年   17119篇
  2009年   16247篇
  2008年   27033篇
  2007年   28707篇
  2006年   28788篇
  2005年   28313篇
  2004年   27212篇
  2003年   26300篇
  2002年   25832篇
  2001年   42112篇
  2000年   43287篇
  1999年   36883篇
  1998年   10294篇
  1997年   9447篇
  1996年   9374篇
  1995年   8719篇
  1994年   8253篇
  1993年   7745篇
  1992年   28680篇
  1991年   27412篇
  1990年   26834篇
  1989年   25742篇
  1988年   23945篇
  1987年   23526篇
  1986年   22637篇
  1985年   21539篇
  1984年   16110篇
  1983年   13725篇
  1982年   8262篇
  1981年   7210篇
  1979年   14883篇
  1978年   10410篇
  1977年   8815篇
  1976年   8284篇
  1975年   9117篇
  1974年   10883篇
  1973年   10347篇
  1972年   9827篇
  1971年   9048篇
  1970年   8727篇
  1969年   8184篇
  1968年   7827篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Neurological Sciences - Chronic subdural haematoma (CSDH) is one of the most common neurosurgical pathologies. The recurrence of chronic subdural haematomas is an important concern, considering...  相似文献   
132.
133.
This paper reviews the published literature on a group of developmental disorders of the retina and retinal pigment epithelium which result in focal abnormalities in one or both eyes. They are often asymptomatic, found on routine examination and are generally non-progressive. Some are associated with other systemic abnormalities.Subject terms: Retinal diseases, Eye abnormalities  相似文献   
134.
135.
Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods.  相似文献   
136.
137.
138.
139.
Recurrent herpes labialis (RHL) is an incredibly common condition, though the medical literature evaluating pediatric aspects is limited. This paper assesses prevalence and therapeutic studies of pediatric RHL as well as disease complications. A comprehensive literature search of English‐language citations based on PubMed queries of selected terms was performed, with exclusion if methodology was not discussed, or if studies had 10 or fewer patients. RHL prevalence in pediatrics has been assessed by measures of point and periodic prevalence, though methodologic limitations may under‐ or over‐estimate the true prevalence of RHL. Studies have been conducted to evaluate therapeutic safety, tolerability, and efficacy of antivirals in the pediatric population. Pediatric RHL point prevalence ranges from 0.72% to 5.2% depending on the population study and the methodologies used. Pediatric RHL carries a significant public health burden and is often implicated in patients with eczema herpeticum, erythema multiforme, reactive infectious mucositis eruptions, and hypersensitivity reactions. There are few studies that evaluate the rates of occurrence of these sequelae associated with pediatric RHL.  相似文献   
140.
We consider the scenario where there is an exposure, multiple biologically defined sets of biomarkers, and an outcome. We propose a new two-step procedure that tests if any of the sets of biomarkers mediate the exposure/outcome relationship, while maintaining a prespecified familywise error rate. The first step of the proposed procedure is a screening step that removes all groups that are unlikely to be strongly associated with both the exposure and the outcome. The second step adapts recent advances in postselection inference to test if there are true mediators in each of the remaining candidate sets. We use simulation to show that this simple two-step procedure has higher statistical power to detect true mediating sets when compared with existing procedures. We then use our two-step procedure to identify a set of Lysine-related metabolites that potentially mediate the known relationship between increased body mass index and the increased risk of estrogen-receptor positive breast cancer in postmenopausal women.  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