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   2852827篇
  免费   198453篇
  国内免费   8004篇
耳鼻咽喉   36412篇
儿科学   94015篇
妇产科学   76454篇
基础医学   393548篇
口腔科学   73913篇
临床医学   256672篇
内科学   566415篇
皮肤病学   65182篇
神经病学   239248篇
特种医学   112226篇
外国民族医学   742篇
外科学   429234篇
综合类   54381篇
现状与发展   7篇
一般理论   1101篇
预防医学   220365篇
眼科学   61931篇
药学   204798篇
  11篇
中国医学   6152篇
肿瘤学   166477篇
  2021年   22108篇
  2019年   22773篇
  2018年   50476篇
  2017年   39238篇
  2016年   45034篇
  2015年   32952篇
  2014年   44966篇
  2013年   66434篇
  2012年   94190篇
  2011年   110862篇
  2010年   71889篇
  2009年   63682篇
  2008年   103522篇
  2007年   110828篇
  2006年   94377篇
  2005年   92106篇
  2004年   89803篇
  2003年   87476篇
  2002年   82688篇
  2001年   129804篇
  2000年   132512篇
  1999年   111870篇
  1998年   33116篇
  1997年   29460篇
  1996年   29446篇
  1995年   28510篇
  1994年   26074篇
  1993年   24365篇
  1992年   85805篇
  1991年   82244篇
  1990年   79381篇
  1989年   76592篇
  1988年   69978篇
  1987年   68476篇
  1986年   63970篇
  1985年   60970篇
  1984年   45484篇
  1983年   38471篇
  1982年   23129篇
  1981年   20607篇
  1979年   39280篇
  1978年   27770篇
  1977年   23603篇
  1976年   21819篇
  1975年   23090篇
  1974年   27031篇
  1973年   25592篇
  1972年   23906篇
  1971年   22084篇
  1970年   20323篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
82.
Henna, derived from a combination of natural leaves and coloring additives, is a common decorative dye traditionally used in many Islamic religious celebrations. Para‐phenylenediamine (PPD), a major component of black henna tattoo, is a strong sensitizer and common allergen. We report a case of severe connubial allergic contact dermatitis after black henna heterotransfer in a girl.  相似文献   
83.
84.
85.
86.
Acne vulgaris (acne) is a chronic inflammatory disease of the sebaceous gland, characterized by follicular hyperkeratinization, excessive colonization by Propionibacterium acnes (Pacnes) as well as immune reactions and inflammation. Despite an armamentarium of topical treatments available including benzoyl peroxide, retinoids and azelaic acid, topical antibiotics in monotherapies, especially erythromycin and clindamycin, are still used in Europe to treat acne. This intensive use led to antimicrobial‐resistant P. acnes and staphylococci strains becoming one of the main health issues worldwide. This is an update on the current topical acne treatments available in Europe, their mechanism of action, their potential to induce antimicrobial resistance and their clinical efficacy and safety.  相似文献   
87.
We report on a child with several café au lait spots in association with a lumbar lipomeningomyelocele as an apparently new association. Cutaneous markers, the identification of which plays a crucial role in the early diagnosis and management of spinal malformations, can accompany occult spinal dysraphism. Herein we report a case of lumbar lipomeningomyelocele associated with an overlying café au lait spot that served as a marker of occult spinal dysraphism. The patient also had segmental café au lait spots on the face, making the association unique.  相似文献   
88.
89.
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation.  相似文献   
90.
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