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   465篇
  免费   24篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   4篇
妇产科学   10篇
基础医学   77篇
口腔科学   10篇
临床医学   42篇
内科学   103篇
皮肤病学   8篇
神经病学   28篇
特种医学   9篇
外科学   62篇
综合类   3篇
一般理论   2篇
预防医学   43篇
眼科学   6篇
药学   32篇
中国医学   3篇
肿瘤学   46篇
  2023年   1篇
  2022年   12篇
  2021年   16篇
  2020年   6篇
  2019年   8篇
  2018年   14篇
  2017年   12篇
  2016年   15篇
  2015年   10篇
  2014年   13篇
  2013年   21篇
  2012年   37篇
  2011年   43篇
  2010年   13篇
  2009年   14篇
  2008年   33篇
  2007年   41篇
  2006年   31篇
  2005年   24篇
  2004年   22篇
  2003年   34篇
  2002年   18篇
  2001年   4篇
  1999年   1篇
  1998年   4篇
  1997年   3篇
  1996年   3篇
  1995年   5篇
  1994年   5篇
  1993年   3篇
  1992年   2篇
  1991年   2篇
  1990年   3篇
  1989年   1篇
  1988年   3篇
  1987年   2篇
  1986年   3篇
  1984年   2篇
  1982年   2篇
  1980年   1篇
  1978年   1篇
  1977年   1篇
  1975年   1篇
排序方式: 共有490条查询结果,搜索用时 15 毫秒
51.
Antibiotic susceptibility testing was performed on 71 Acinetobacter baumannii clinical isolates, and presence of antibiotic resistance genes was screened for by PCR amplification and sequencing. Resistance rates were very high for aminoglycosides (22–80%), fluoroquinolones (>90%), and cephalosporins (>90%) but remained low for rifampin (2.8%) or null for colistin. Antibiotic resistance encoding genes detected were as follows: blaTEM-128 gene (74.6%), aph(3′)-VI (50.7 %), aadA (63.4%), ant(2″)-I (14.1%), aac(3)-Ia (91.1%), aac(6′)-Ib (4.2%), mutation Ser83Leu in gyrA (94.4%), double mutations Ser83Leu and Ser80Leu (or Ser84Leu) in gyrA and parC (69.0%), and mutation I581N in RRDR of the rpoB gene.  相似文献   
52.
53.
Since its’ discovery over 20 years ago, BDNF has been shown to play a key role in neuronal survival, in promoting neuronal regeneration following injury, regulating transmitter systems and attenuating neural-immune responses. Estrogen’s actions in the young and mature brain, and its role in neurodegenerative diseases in many cases overlaps with those observed for BDNF. Reduced estrogen and BDNF are observed in patients with Parkinson’s disease and Alzheimer’s disease, while high estrogen levels are a risk factor for development of multiple sclerosis. Estrogen receptors, which transduce the actions of estrogen, colocalize to cells that express BDNF and its receptor trkB, and estrogen further regulates the expression of this neurotrophin system. This review describes the distribution of BDNF and trkB expressing cells in the forebrain, and the roles of estrogen and the BDNF–trkB neurotrophin system in Parkinson’s disease, Alzheimer’s disease and multiple sclerosis.  相似文献   
54.
55.
56.
57.
58.
Tattoos have long become a part of human civilization. However, as the number of people who get tattoos increases, so is the number of people who wish to have their tattoos removed. Compared to other methods, laser‐based devices are associated with the best efficacy and least side effects in tattoo removal. Lack of understanding of the fundamental principles of laser and managing its parameters may result in suboptimal result and increased risk of side effects. Recognizing and mastering multiple factors including skin types, nature and color of tattoos, and proper selection of laser parameters such as wavelength, fluence, and pulse, are central in achieving an optimal tattoo removal outcome. This review provides a comprehensive overview on the fundamental principle of laser and practical approaches in tattoo removal.  相似文献   
59.
Summary: A case of urethral coitus is presented in which the patient had maximum urethral dilation and good urinary control and had no symptoms of cystitis. She had a left hypoplastic kidney, cervicodorsal kyphoscoliosis, and absent internal genitalia.  相似文献   
60.
This paper presents a graph-based segmentation method using multiple criteria in successive stages to segment thoracoscopic images acquired during a diskectomy procedure commonly used for thoracoscopic anterior release and fusion for scoliosis treatment. Starting with image pre-processing, including Gaussian smoothing, brightness and contrast enhancement, and histogram thresholding, a standard graph-based method is applied to produce a coarse segmentation of thoracoscopic images. Next, regions are further merged in a multistage graph-based process based on features like grey-level similarity, region size and common edge length. Experimental results show that our approach achieves good spatial coherence, accurate edge location and appropriate segmentation of the regions of interest from a sequence of thoracoscopic images.  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