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   1406997篇
  免费   103944篇
  国内免费   9729篇
耳鼻咽喉   20321篇
儿科学   40907篇
妇产科学   39585篇
基础医学   194680篇
口腔科学   41225篇
临床医学   123672篇
内科学   270762篇
皮肤病学   30759篇
神经病学   110478篇
特种医学   56605篇
外国民族医学   491篇
外科学   214806篇
综合类   45839篇
一般理论   449篇
预防医学   96608篇
眼科学   34132篇
药学   108384篇
  84篇
中国医学   8693篇
肿瘤学   82190篇
  2018年   14641篇
  2017年   12290篇
  2016年   12809篇
  2015年   15759篇
  2014年   21712篇
  2013年   29405篇
  2012年   39127篇
  2011年   41952篇
  2010年   25179篇
  2009年   23693篇
  2008年   37900篇
  2007年   40883篇
  2006年   41636篇
  2005年   40474篇
  2004年   37660篇
  2003年   36560篇
  2002年   35630篇
  2001年   65244篇
  2000年   67007篇
  1999年   56996篇
  1998年   15194篇
  1997年   13890篇
  1996年   13156篇
  1995年   13126篇
  1994年   12220篇
  1992年   43250篇
  1991年   41724篇
  1990年   40940篇
  1989年   39889篇
  1988年   37235篇
  1987年   36640篇
  1986年   35058篇
  1985年   33244篇
  1984年   24851篇
  1983年   21013篇
  1982年   12635篇
  1981年   11526篇
  1979年   23877篇
  1978年   17016篇
  1977年   14759篇
  1976年   13331篇
  1975年   15216篇
  1974年   18039篇
  1973年   17534篇
  1972年   16788篇
  1971年   15694篇
  1970年   14874篇
  1969年   14320篇
  1968年   13438篇
  1967年   11990篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Tamoxifen prevents recurrence of breast cancer and is suggested for preventive risk-reducing therapy. Tamoxifen reduces mammographic density, a proxy for therapy response, but little is known about its effects in remodelling normal breast tissue. Our study, a substudy within the double-blinded dose-determination trial KARISMA, investigated tamoxifen-specific changes in breast tissue composition and histological markers in healthy women. We included 83 healthy women randomised to 6 months daily intake of 20, 10, 5, 2.5, 1 mg of tamoxifen or placebo. The groups were combined to “no dose” (0-1 mg), “low-dose” (2.5-5 mg) or “high-dose” (10-20 mg) of tamoxifen. Ultrasound-guided biopsies were collected before and after tamoxifen exposure. In each biopsy, epithelial, stromal and adipose tissues was quantified, and expression of epithelial and stromal Ki67, oestrogen receptor (ER) and progesterone receptor (PR) analysed. Mammographic density using STRATUS was measured at baseline and end-of-tamoxifen-exposure. We found that different doses of tamoxifen reduced mammographic density and glandular-epithelial area in premenopausal women and associated with reduced epithelium and increased adipose tissue. High-dose tamoxifen also decreased epithelial ER and PR expressions in premenopausal women. Premenopausal women with the greatest reduction in proliferation also had the greatest epithelial reduction. In postmenopausal women, high-dose tamoxifen decreased the epithelial area with no measurable density decrease. Tamoxifen at both low and high doses influences breast tissue composition and expression of histological markers in the normal breast. Our findings connect epithelial proliferation with tissue remodelling in premenopausal women and provide novel insights to understanding biological mechanisms of primary prevention with tamoxifen.  相似文献   
2.
3.
4.
Oral squamous cell carcinomas (OSCCs) develop in genetically altered epithelium in the mucosal lining, also coined as fields, which are mostly not visible but occasionally present as white oral leukoplakia (OL) lesions. We developed a noninvasive genetic assay using next-generation sequencing (NGS) on brushed cells to detect the presence of genetically altered fields, including those that are not macroscopically visible. The assay demonstrated high accuracy in OL patients when brush samples were compared with biopsies as gold standard. In a cohort of Fanconi anemia patients, detection of mutations in prospectively collected oral brushes predicted oral cancer also when visible abnormalities were absent. We further provide insight in the molecular landscape of OL with frequent changes of TP53, FAT1 and NOTCH1. NGS analysis of noninvasively collected samples offers a highly accurate method to detect genetically altered fields in the oral cavity, and predicts development of OSCC in high-risk individuals. Noninvasive genetic screening can be employed to screen high-risk populations for cancer and precancer, map the extension of OL lesions beyond what is visible, map the oral cavity for precancerous changes even when visible abnormalities are absent, test accuracy of promising imaging modalities, monitor interventions and determine genetic progression as well as the natural history of the disease in the human patient.  相似文献   
5.
6.
Graefe's Archive for Clinical and Experimental Ophthalmology - Ferromagnetic foreign bodies (FFB) present during magnetic resonance imaging (MRI) explorations can lead to tissue injury due to...  相似文献   
7.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz -  相似文献   
8.
9.
Immunologic Research - Hyper immunoglobulin M (HIGM) syndrome is a rare disorder of the immune system with impaired antibody functions. The clinical picture of the patients varies according to the...  相似文献   
10.
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