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   2355205篇
  免费   181671篇
  国内免费   7748篇
耳鼻咽喉   31948篇
儿科学   77684篇
妇产科学   66614篇
基础医学   332661篇
口腔科学   66021篇
临床医学   207741篇
内科学   469561篇
皮肤病学   53521篇
神经病学   189753篇
特种医学   94574篇
外国民族医学   617篇
外科学   365635篇
综合类   52680篇
现状与发展   3篇
一般理论   711篇
预防医学   183436篇
眼科学   52533篇
药学   172051篇
  6篇
中国医学   4259篇
肿瘤学   122615篇
  2018年   22902篇
  2016年   20817篇
  2015年   23532篇
  2014年   32783篇
  2013年   49595篇
  2012年   63647篇
  2011年   68196篇
  2010年   41795篇
  2009年   40179篇
  2008年   64763篇
  2007年   69771篇
  2006年   71174篇
  2005年   69359篇
  2004年   66567篇
  2003年   64787篇
  2002年   62577篇
  2001年   108231篇
  2000年   111419篇
  1999年   93887篇
  1998年   27927篇
  1997年   25067篇
  1996年   25938篇
  1995年   25392篇
  1994年   23958篇
  1993年   22326篇
  1992年   77527篇
  1991年   75962篇
  1990年   73960篇
  1989年   70944篇
  1988年   66140篇
  1987年   64828篇
  1986年   61674篇
  1985年   59169篇
  1984年   44812篇
  1983年   38326篇
  1982年   23626篇
  1981年   21109篇
  1980年   19793篇
  1979年   41520篇
  1978年   29742篇
  1977年   25334篇
  1976年   23607篇
  1975年   25356篇
  1974年   29878篇
  1973年   28647篇
  1972年   26867篇
  1971年   24890篇
  1970年   22937篇
  1969年   21875篇
  1968年   20575篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Imaging     
  相似文献   
43.
44.
45.
Infections due to Penicillium species other than P.marneffei are rare. We identified a boy with X-linked chronic granulomatous disease (X-CGD) with a pulmonary nodule and adjacent rib osteomyelitis caused by Penicillium piceum. The only sign of infection was an elevated sedimentation rate. P. piceum was isolated by fine needle aspirate and from excised infected tissues. Surgical removal and one year of voriconazole treatment were very well tolerated and led to complete recovery. Microbiological, microscopic and molecular studies support the fungal diagnosis. P. piceum should be considered as a relevant pathogen in immunocompromised patients.  相似文献   
46.
47.
48.
49.
BACKGROUND: Three dimensional skin equivalents are widely used in dermatopharmacological and toxicological studies and as autologous transplants in wound healing. In pharmacology, there is tremendous need for monitoring the response of engineered skin equivalents to external treatment. Transplantation of skin equivalents for wound healing requires careful verification of their quality prior to transplantation. Optical coherence tomography (OCT) is a non-contact, non-destructive imaging technique for living tissues offering the potential to fulfill these needs. This work presents an analysis of OCT for high-resolution monitoring of skin equivalents at different stages during the culture process. METHODS: We developed a high-resolution OCT imaging setup based on a commercially available OCT system. A broadband femtosecond laser light source replaces the original superluminescence diode. Tomograms of living skin equivalents were recorded with an axial resolution of 3 mum and correlated with histology and immunofluorescence images. Comparison with standard low-resolution OCT is presented to emphasize the advantages of high-resolution OCT for this application. RESULTS: OCT is particularly able to distinguish between different layers of skin equivalents including stratum corneum, epidermal and dermal layer as well as the basement membrane zone. The high-resolution OCT scans correlate closely with two key benchmarks, histology and immunofluorescence imaging. CONCLUSIONS: This study clearly demonstrates the benefits of high-resolution OCT for identifying living tissue structure and morphology. Compared with the current gold standard histology, OCT offers non-destructive tissue imaging, enabling high-resolution evaluation of living tissue morphology and structure as it evolves.  相似文献   
50.
BACKGROUND: Computer-assisted image analysis has been proposed for human hair growth studies. METHODS: The performances of Trichoscan, a commercially available automated system combining epiluminiscence microscopy with digital image analysis, developed for office-based hair growth measurements, have been evaluated comparatively on the same skin sites using standardized photographic equipment and calibrated processing for contrast-enhanced phototrichogram (CE-PTG) analysis. This reference method has been validated with scalp biopsies and histological examination of serial sectioning. RESULTS: Besides edge effects, hair fibres escaped the Trichoscan analysis for various reasons including, but not limited to, thickness, pigmentation, closeness and crossing. CONCLUSION: Most of these problems have been identified in the late 1980s and remain largely unsolved by the processing software that was evaluated in 2004. Therefore claims promoting the Trichoscan method for accurate hair measurements in clinical trials on scalp and body hair are not supported by the present investigation. The speed at which the analysis is performed is outweighed by the errors in signal detection. Therefore we suggest that improvements must be clearly documented before Trichoscan is established for quantified diagnostic purposes and detailed hair cycle monitoring during hair trials.  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