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   4078362篇
  免费   302208篇
  国内免费   10243篇
耳鼻咽喉   57517篇
儿科学   130525篇
妇产科学   111227篇
基础医学   569387篇
口腔科学   117112篇
临床医学   375854篇
内科学   790614篇
皮肤病学   91311篇
神经病学   338523篇
特种医学   158707篇
外国民族医学   1438篇
外科学   611077篇
综合类   91306篇
现状与发展   6篇
一般理论   1728篇
预防医学   325793篇
眼科学   95052篇
药学   301687篇
  11篇
中国医学   7998篇
肿瘤学   213940篇
  2018年   43757篇
  2017年   33644篇
  2016年   38242篇
  2015年   43158篇
  2014年   60772篇
  2013年   92359篇
  2012年   122667篇
  2011年   130196篇
  2010年   78061篇
  2009年   74642篇
  2008年   122142篇
  2007年   129768篇
  2006年   131510篇
  2005年   127167篇
  2004年   122551篇
  2003年   118202篇
  2002年   115043篇
  2001年   187101篇
  2000年   192581篇
  1999年   163358篇
  1998年   48570篇
  1997年   43343篇
  1996年   42974篇
  1995年   41672篇
  1994年   38689篇
  1993年   36207篇
  1992年   129799篇
  1991年   125558篇
  1990年   121361篇
  1989年   117280篇
  1988年   108386篇
  1987年   106774篇
  1986年   100836篇
  1985年   96614篇
  1984年   72686篇
  1983年   62079篇
  1982年   37427篇
  1981年   33683篇
  1979年   66781篇
  1978年   47272篇
  1977年   40072篇
  1976年   37538篇
  1975年   39639篇
  1974年   48030篇
  1973年   45850篇
  1972年   43138篇
  1971年   39946篇
  1970年   37322篇
  1969年   35292篇
  1968年   32465篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
85.
86.
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   
87.
ABSTRACT: Background: Although increases in perinatal mortality risk associated with fetal macrosomia are well documented, the optimal route of delivery for fetuses with suspected macrosomia remains controversial. The objective of this investigation was to assess the risk of neonatal death among macrosomic infants delivered vaginally compared with those delivered by cesarean section. Methods: Data were derived from the U.S. 1995–1999 Linked Live Birth‐Infant Death Cohort files and term (37–44 wk), single live births to United States resident mothers selected. A proportional hazards model was used to analyze the risk of neonatal death associated with cesarean delivery among 3 categories of macrosomic infants (infants weighing 4,000–4,499 g; 4,500–4,999 g; and 5,000+ g). Results: After controlling for maternal characteristics and complications, the adjusted hazard ratio for neonatal death associated with cesarean delivery among the 3 categories of macrosomic infants was 1.40, 1.30, and 0.85. Conclusions: Although cesarean delivery may reduce the risk of death for the heaviest infants (5,000+ g), the relative benefit of this intervention for macrosomic infants weighing 4,000–4,999 g remains debatable. Thus, policies in support of prophylactic cesarean delivery for suspected fetal macrosomia may need to be reevaluated. (BIRTH 33:4 December 2006)  相似文献   
88.
89.
90.
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   
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