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   1498篇
  免费   72篇
  国内免费   26篇
耳鼻咽喉   5篇
儿科学   48篇
妇产科学   39篇
基础医学   179篇
口腔科学   80篇
临床医学   145篇
内科学   367篇
皮肤病学   48篇
神经病学   99篇
特种医学   146篇
外科学   141篇
综合类   74篇
预防医学   98篇
眼科学   27篇
药学   46篇
中国医学   4篇
肿瘤学   50篇
  2023年   11篇
  2022年   20篇
  2021年   28篇
  2020年   21篇
  2019年   31篇
  2018年   31篇
  2017年   22篇
  2016年   50篇
  2015年   36篇
  2014年   48篇
  2013年   89篇
  2012年   60篇
  2011年   72篇
  2010年   56篇
  2009年   48篇
  2008年   59篇
  2007年   65篇
  2006年   43篇
  2005年   38篇
  2004年   42篇
  2003年   29篇
  2002年   43篇
  2001年   24篇
  2000年   26篇
  1999年   24篇
  1998年   56篇
  1997年   51篇
  1996年   36篇
  1995年   28篇
  1994年   33篇
  1993年   36篇
  1992年   8篇
  1991年   11篇
  1990年   17篇
  1989年   38篇
  1988年   24篇
  1987年   24篇
  1986年   16篇
  1985年   8篇
  1984年   11篇
  1983年   9篇
  1982年   10篇
  1981年   10篇
  1980年   11篇
  1977年   6篇
  1976年   8篇
  1975年   7篇
  1972年   6篇
  1963年   6篇
  1941年   11篇
排序方式: 共有1596条查询结果,搜索用时 15 毫秒
81.
OBJECTIVE: To analyze variations in early neonatal mortality, stillbirth rates, and a set of indicators collected from obstetric hospitals affiliated to the Brazilian National Unified Health System (SUS) for their monitoring through the Hospital Data System (SIH/SUS) and Live Births Data System (SINASC). METHODS: One-hundred and thirty five hospitals in the state of Rio de Janeiro were assessed in 1997. Factor analysis was conducted using principal components. Score distribution for the first two components were established, which allowed to classify hospitals according to maternal risk profile and care outcomes. RESULTS: Hospitals affiliated to SUS were responsible for 77.8% of all deliveries in the state of Rio de Janeiro and 23% of them performed fewer than 100 deliveries a year. Among hospitals of extreme high maternal risk and low performance, there were several units considered as referral centers for high-risk pregnancy. It was also observed that 5% of hospital units with low complexity infrastructures showed a profile of high maternal risk and questionable care outcomes. CONCLUSIONS: The Hospital Information Data System affiliated to the National Unified Health System has proven to be an important information source for monitoring hospital stillbirth and early neonatal mortality rates as well as for planning surveillance actions for health services providing obstetric and/or neonatal care.  相似文献   
82.
83.
84.
Cocaine use in pregnancy in Amsterdam   总被引:1,自引:0,他引:1  
To study the effects of cocaine use in pregnancy in Amsterdam, clinical data on cocaine-using pregnant women ( n = 21) and their offspring ( n = 23) were obtained retrospectively (1987–1994) at the Academic Medical Center, Amsterdam. Infants exposed to cocaine had a median gestational age of 39 weeks and a median birth weight of 3090 g. There were six preterm infants, two small-for-gestational-age infants and five infants with a small head circumference. Three infants had a congenital malformation. One infant (Potter's syndrome) died shortly before birth. One infant had congenital syphilis, four had intracerebral abnormalities on ultrasound and four had abnormal neurologic symptoms in the neonatal period. One infant died after 21 days of life. At follow-up four infants showed abnormal development. In 12 of the 23 infants (52%), one or more possible effects of cocaine were found.  相似文献   
85.
OBJECTIVE: Cardiac catheterization has begun to be employed for therapeutic purposes since the middle sixties. In this paper the authors review the current indications, technique and results related to each of the interventional procedures. It also includes a brief sample of the Instituto Dante Pazzanese experience for illustrative purpose. METHODS: The main procedures that are addressed include balloon and blade atrial septostomy (Rashkind and Park procedures), pulmonary valvuloplasty, aortic valvuloplasty, mitral valvuloplasty (for rheumatic mitral stenosis), angioplasty for coarctation of aorta with or without stent implantation, angioplasty for pulmonary artery stenosis with or without stent implantation, percutaneous occlusion of the patent ductus arteriosus, percutaneous occlusion of atrial septal defects and balloon dilation of stenosed Blalock-Taussig shunts. The authors make a review of the most important papers published in the literature about Interventional Pediatric Cardiology, including their own experience. RESULTS: Good or excelent therapeutic results are achieved for pulmonic stenosis, coarctation of aorta, patent ductus arteriosus, atrial septal defects and pulmonary branch stenosis. Satisfactory palliations are obtained for aortic stenosis, rheumatic mitral stenosis and complex congenital heart diseases that require balloon atrial septostomy. CONCLUSIONS: Due to the recent technological development, pediatric therapeutic heart catheterization makes it possible to treat or palliate about 30% of all congenital or acquired heart diseases with encouraging results, sparing some patients from the need of cardiac surgery.  相似文献   
86.
87.
88.
Lymphocytes activated by mitogenic lectins display changes in transmembrane potential, an elevation in the cytoplasmic Ca2+ concentrations, proliferation and/or activation induced cell death. Low concentrations of ouabain (an inhibitor of Na+,K+-ATPase) suppress mitogen-induced proliferation and increases cell death. To understand the mechanisms involved, a number of parameters were analyzed using fluorescent probes and flow cytometry. The addition of 100 nM ouabain to cultures of peripheral blood lymphocytes activated with 5 microg/ml phytohemagglutinin (PHA) did not modify the increased expression of the Fas receptor or its ligand FasL induced by the mitogen. However, treatment with ouabain potentiated apoptosis induced by an anti-Fas agonist antibody. A synergy between ouabain and PHA was also observed with regard to plasma membrane depolarization. PHA per se did not induce dissipation of mitochondrial membrane potential but when cells were also exposed to ouabain a marked depolarization could be observed, and this was a late event. It is possible that the inhibitory effect of ouabain on activated peripheral blood lymphocytes involves the potentiation of some of the steps of the apoptotic process and reflects an exacerbation of the mechanism of activation-induced cell death.  相似文献   
89.
90.
The aim of this study was to evaluate the performance of two different glass-ionomer cements: a high-density (Ketac Molar - ESPE) and a resin-modified cement (Fuji VIII - GC) using the Atraumatic Restorative Treatment technique to restore multisurface cavities in permanent teeth. A total of 60 ART restorations (30 with each material) were placed in schoolchildren (9-16 years of age) by two operators. After a period of 6 months, two independent examiners evaluated 59 restorations according to the criteria used in previous ART studies. Data were submitted to McNemar and Fischer tests. The success rate of the treatment was 98.3%. One restoration (Ketac Molar) was replaced by another material and was recorded as failure. The success rates of the restorations were 100% and 96.6% for Fuji VIII and Ketac Molar, respectively. There was no statistically significant difference in the restorations success between baseline and 6 months (p>0.05). In the same way, no significant differences were found between materials, cavity types or operators (p>0.05). The ART approach was highly appropriate and effective in restorations involving two or more tooth surfaces, after 6 months. The results showed a promising performance of the ART technique with both materials.  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