首页 | 官方网站   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   563篇
  免费   36篇
医药卫生   599篇
  2023年   4篇
  2022年   4篇
  2021年   13篇
  2020年   10篇
  2019年   22篇
  2018年   16篇
  2017年   13篇
  2016年   13篇
  2015年   11篇
  2014年   16篇
  2013年   18篇
  2012年   25篇
  2011年   25篇
  2010年   17篇
  2009年   14篇
  2008年   17篇
  2007年   27篇
  2006年   25篇
  2005年   26篇
  2004年   21篇
  2003年   16篇
  2002年   24篇
  2001年   19篇
  2000年   24篇
  1999年   23篇
  1998年   4篇
  1997年   4篇
  1995年   8篇
  1993年   4篇
  1992年   12篇
  1991年   9篇
  1990年   9篇
  1989年   9篇
  1988年   6篇
  1987年   5篇
  1986年   6篇
  1985年   4篇
  1984年   4篇
  1983年   6篇
  1979年   6篇
  1978年   4篇
  1976年   5篇
  1975年   3篇
  1974年   6篇
  1973年   5篇
  1972年   5篇
  1971年   5篇
  1970年   3篇
  1969年   4篇
  1967年   6篇
排序方式: 共有599条查询结果,搜索用时 15 毫秒
101.
Neural tube defects (NTDs) constitute a major group of congenital malformations with an overall incidence of approximately 1-2 in 1,000 live births in the United States. Hispanic Americans have a 2.5 times higher risk than the Caucasian population. Spina bifida meningomyelocele (SBMM) is a major clinical presentation of NTDs resulting from lack of closure of the spinal cord caudal to the head. In a previous study of spina bifida (SB) patients of European Caucasian descent, it was suggested that specific haplotypes of the platelet-derived growth factor receptor-alpha (PDGFRA) gene P1 promoter strongly affected the rate of NTD genesis. In our study, we evaluated the association of PDGFRA P1 in a group of 407 parent-child triads (167 Caucasian, 240 Hispanics) and 164 unrelated controls (89 Caucasian, 75 Hispanic). To fully evaluate the association of PDGFRA P1, we performed both transmission-disequilibrium test (TDT) and association analyses to test the hypotheses that PDGFRA P1 was (1) transmitted preferentially in SBMM affected children and (2) associated with the condition of SBMM comparing affected children to unaffected controls. We did find that there was a different allelic and genotypic distribution of PDGFRA P1 when comparing Hispanics and Caucasians. However, neither ethnic group showed strong association between SBMM and the PDGFRA P1 region. These findings suggest that PDGFRA P1 does not have a major role in the development of SBMM.  相似文献   
102.
103.
104.
105.
106.
INTRODUCTION AND BACKGROUND: Quality management (QM) principles generally have not been applied to multi-casualty and disaster situations. Quality management incorporates quality assurance (QA) and quality improvement (QI) supported by a management information system (MIS). Since responders to disasters and multi-casualty incidents generally operate on standing orders and/or protocols, the character of the responses lends itself to quality management methods. Standards and indicators of performance readily can be developed for these situations. OBJECTIVES: 1) to format disaster medical records as data collection instruments; 2) to develop appropriate tools that are easy to use for rapid assessments; 3) to develop a mechanism for determination of causes of injuries; and 4) to develop methods to: a) track patients; b) document response and recovery; and c) document the circumstances associated with the event. METHODS: Model tools using checklists and short, fill-in answers are provided. These tools are designed to be incorporated into the trauma or EMS registries. Emergency medical technicians, nurses, physicians, and medical students scored the same disaster scenario for the functional areas of calling the state of the disaster, triage, and field stabilization. RESULTS: Testing indicated that the checklists are completed in less than one minute, and produce objective data per patient in each functional area evaluated. In one instance, data were compiled for 38 patients from one bus accident in less than 10 minutes. The same data were reproduced, without variation, in the same amount of time, by three different providers of varied professional backgrounds.  相似文献   
107.
The primary cell types that sustain polyomavirus (Py) replication following intranasal infection as well as the nature of the host cellular response to Py were unknown. As this is an essential and specific site for virus entry, it seems likely that viral gene function must be adapted to these mucosal tissues. Using immunohistochemistry and in situ hybridization, we determined the cell types in the lung that support Py gene expression and replication following intranasal inoculation of newborn mice within 24 h of birth. Lungs were collected daily from days 1 to 10 postinfection for Py DNA and early T antigen analysis and for histological examination by H&E staining, using methods that preserve the delicate newborn lung architecture. Viral DNA was present in increasing quantities from 2 to 6 dpi in a subset of the Clara cells lining the inner lumen of the bronchi and bronchioles, while T antigen expression was present in a majority of the cells in the bronchi and bronchiole lumen. A distinct and transient pattern of hyperplasia was observed among the cells expressing T antigen and was present from 3 through 6 dpi. Py DNA-containing cells exfoliated into the bronchiole lumen and alveolar ducts, but Py T antigen was not detected in these cells. Py DNA was first detected at 2 dpi, increased through 6 dpi, and abruptly declined through 9 dpi at which time there was no sign of viral DNA in the lungs by in situ hybridization. An unusual infiltration of neutrophils began before the presence of exfoliated cells or Py replication and continued for 2-3 days and was followed by a lymphocytic infiltration at 8-10 dpi lasting 2-3 days. Neither the hyperplasia nor the neutrophil infiltration occurred following infection with the MOP1033 MT-Ag or RB1 LT-Ag mutants of Py. In addition, both the neutrophil infiltration and the transient hyperplasia are in stark contrast to the heavy macrophage infiltration that follows infection of lungs with mouse adenovirus. Thus it appears that Py elicits a distinct host response pattern not seen with other DNA viral infections.  相似文献   
108.
Two cases with complete bronchial stenosis of the mainstem bronchus secondary to thoracic blunt trauma are presented. One patient had hemoneumothorax on the left side, the other one had bilateral hemothorax. Both were initially treated with drainage by thoracostomy tube with partial resolution of the thoracic bloody pleural collection. Later, the two patients developed complete atelectasis of the lung, one on the left side and the other one in the right; this later case was subject to lung decortication. The fiberopticbronchoscopy showed a complete occlusion of the mainstem bronchus in both patients. A bronchoplasty with sleeve resection of the stenotic segment was performed; the lumen of the bronchus was preserved by an end-to-end suture with separate stitchs of Vycryl 0000. Both cases remain without bronchopulmonary pathology after 4 years of follow-up of bronchoplasty. In cases of blunt thoracic trauma, it is important to consider the possibility of bronchial rupture. The importance of bronchoscopic diagnosis and surgical treatment is stressed.  相似文献   
109.
110.
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-23

京公网安备 11010802026262号