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   4074047篇
  免费   301838篇
  国内免费   10240篇
耳鼻咽喉   57499篇
儿科学   130390篇
妇产科学   111153篇
基础医学   568796篇
口腔科学   116970篇
临床医学   375416篇
内科学   789590篇
皮肤病学   91320篇
神经病学   338167篇
特种医学   158713篇
外国民族医学   1438篇
外科学   610159篇
综合类   91180篇
现状与发展   6篇
一般理论   1720篇
预防医学   325364篇
眼科学   94730篇
药学   301482篇
  11篇
中国医学   8028篇
肿瘤学   213993篇
  2018年   43710篇
  2017年   33647篇
  2016年   38240篇
  2015年   43165篇
  2014年   60753篇
  2013年   92199篇
  2012年   122540篇
  2011年   130011篇
  2010年   77969篇
  2009年   74526篇
  2008年   121973篇
  2007年   129533篇
  2006年   131267篇
  2005年   126921篇
  2004年   122294篇
  2003年   117889篇
  2002年   114714篇
  2001年   187060篇
  2000年   192552篇
  1999年   163313篇
  1998年   48492篇
  1997年   43279篇
  1996年   42909篇
  1995年   41620篇
  1994年   38636篇
  1993年   36154篇
  1992年   129764篇
  1991年   125532篇
  1990年   121336篇
  1989年   117250篇
  1988年   108366篇
  1987年   106747篇
  1986年   100818篇
  1985年   96580篇
  1984年   72639篇
  1983年   62032篇
  1982年   37355篇
  1981年   33616篇
  1979年   66747篇
  1978年   47234篇
  1977年   40023篇
  1976年   37492篇
  1975年   39594篇
  1974年   47988篇
  1973年   45810篇
  1972年   43106篇
  1971年   39923篇
  1970年   37307篇
  1969年   35276篇
  1968年   32453篇
排序方式: 共有10000条查询结果,搜索用时 0 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