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   189篇
  免费   6篇
  国内免费   3篇
儿科学   10篇
妇产科学   2篇
基础医学   15篇
口腔科学   11篇
临床医学   11篇
内科学   42篇
皮肤病学   9篇
神经病学   5篇
特种医学   35篇
外科学   15篇
综合类   8篇
预防医学   3篇
眼科学   10篇
药学   6篇
肿瘤学   16篇
  2023年   1篇
  2021年   3篇
  2020年   1篇
  2019年   1篇
  2018年   2篇
  2017年   1篇
  2016年   4篇
  2015年   1篇
  2014年   8篇
  2013年   12篇
  2012年   4篇
  2011年   3篇
  2010年   10篇
  2009年   20篇
  2008年   7篇
  2007年   7篇
  2006年   4篇
  2005年   5篇
  2004年   3篇
  2003年   3篇
  2001年   2篇
  2000年   2篇
  1999年   4篇
  1998年   11篇
  1997年   12篇
  1996年   11篇
  1995年   9篇
  1994年   5篇
  1993年   6篇
  1992年   3篇
  1990年   2篇
  1989年   5篇
  1988年   2篇
  1987年   5篇
  1986年   5篇
  1985年   3篇
  1984年   1篇
  1983年   1篇
  1981年   2篇
  1980年   3篇
  1979年   1篇
  1978年   2篇
  1976年   1篇
排序方式: 共有198条查询结果,搜索用时 11 毫秒
61.
Objective. The aim of this article is to review the current knowledge of Doppler ultrasound in canine pregnancy. A brief introduction of Doppler principles and their applications in human obstetrics is also included. Methods. A review of the peer‐reviewed published literature was conducted of the articles pertaining to the use of Doppler ultrasound in canine pregnancy, general Doppler principles, and Doppler applications in human obstetrics. Results. In bitches, Doppler ultrasound has been used to assess ovarian, uterine, umbilical, fetal aorta, common carotid artery, and fetal caudal vena cava blood flow during normal gestation. Most of these vessels increase their blood flow during normal pregnancy. The resistive index and systolic/diastolic ratio of the uterine arteries have been recently described in an experimental pharmacologically induced model of abnormal canine gestation. Both indices progressively increase up to abortion, probably because of progesterone deprivation. Moreover, resistive index abnormalities have been found in canine cases of spontaneous abnormal gestations as described in human medicine. Conclusions. Doppler ultrasound is a useful method for assessing development of the placental and fetal circulation during normal and abnormal canine pregnancy. Further studies are still necessary to widely use this technique in clinical practice.  相似文献   
62.
BACKGROUND: Intravenously administered perfluorocarbon (PFC) emulsions increase oxygen solubility in plasma. PFC might therefore temporarily replace red cells (RBCs) lost during intraoperative hemorrhage. In patients who have undergone hemodilution, the return of autologous blood may be delayed by the administration of PFC, and autologous RBCs may be saved for transfusion after surgical bleeding is stopped and PFC is cleared by the reticuloendothelial system. STUDY DESIGN AND METHODS: In 22 anesthetized, hemodiluted dogs (hemoglobin [Hb] 7 g/dL) breathing 100-percent O2, an intraoperative volume-compensated blood loss was simulated. The efficacy of three therapeutic regimens in maintaining tissue oxygenation was compared: 1) RBC group (n = 7): maintenance of a Hb > 7 g per dL by transfusion of autologous RBCs; 2) PFC group (n = 7): bolus application of a second-generation PFC emulsion (60% wt/vol perflubron) and further acute normovolemic hemodilution (ANH) to a Hb of 3 g per dL; and 3) control group (n = 7): further ANH alone to a Hb of 3 g per dL. Systemic and myocardial oxygenation status and tissue oxygenation were assessed. RESULTS: Autologous RBCs transfused to maintain a Hb of 7 g per dL preserved hemodynamics and tissue oxygenation during blood loss. In the PFC and control groups, heart rate and cardiac index increased significantly in response to further ANH. Tissue oxygenation was not different in the PFC and the RBC groups. Direct comparison of the PFC and control groups revealed better tissue oxygenation in the PFC group, as reflected by significantly higher mixed venous, coronary venous, and local tissue pO2 on liver and skeletal muscle. CONCLUSION: Bolus intravenous administration of 60- percent (wt/vol) perflubron emulsion and further hemodilution from a Hb of 7 g per dL to one of 3 g per dL were as effective as autologous RBC transfusion in maintaining tissue oxygenation during volume-compensated blood loss designed to mimic surgical bleeding.  相似文献   
63.
64.
65.
The generation of new mouse models of human disease is accelerating rapidly, due to the completion of whole‐genome sequencing efforts and technological advances in the manipulation of the mouse genome. We sought to investigate manpower issues in the provision of histopathology expertise for mouse functional genomics and compared this to the perceived demand from principal investigators (PIs). Through the European Commission (EC)‐funded PRIME pathology training initiative, two questionnaires were devised to collect information from pathologists and EC‐funded PIs on the current provision of mouse histopathology expertise in Europe and the demands for this service. We find that pathological analysis is being performed almost exclusively by professionally qualified pathologists, generally employed in clinical diagnostic posts, where the work is undertaken as collaboration outside of their contractual commitments but without previous training in veterinary or comparative pathology. The results indicate that there is a lack of both trainees and provision of specialist training in this field. Unsurprisingly, the availability of diagnostic expertise and advice falls far short of the number of genetically engineered mice (GEM) being generated for analysis. We analyse these results with reference to previous studies and discuss solutions for the future recruitment, training and funding for pathologists in mouse functional genomics in Europe. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.  相似文献   
66.
67.
68.
69.
Background:  Although community water fluoridation has been one of the cornerstone strategies for the prevention and control of dental caries, questions are still raised regarding its cost-effectiveness. This study assessed the impact of changing dental needs on the cost savings from community water fluoridation in Australia.
Methods:  Net costs were estimated as Costs(programme) minus Costs(averted caries). Averted costs were estimated as the product of caries increment in non-fluoridated community, effectiveness of fluoridation and the cost of a carious surface. Modelling considered four age-cohorts: 6–20, 21–45, 46–65 and 66+ years and three time points 1970s, 1980s, and 1990s. Cost of a carious surface was estimated by conventional and complex methods. Real discount rates (4, 7 (base) and 10%) were utilized.
Results:  With base-case assumptions, the average annual cost savings/person, using Australian dollars at the 2005 level, ranged from $56.41 (1970s) to $17.75 (1990s) (conventional method) and from $249.45 (1970s) to $69.86 (1990s) (complex method). Under worst-case assumptions fluoridation remained cost-effective with cost savings ranging from $24.15 (1970s) to $3.87 (1990s) (conventional method) and $107.85 (1970s) and $24.53 (1990s) (complex method). For 66+ years cohort (1990s) fluoridation did not show a cost saving, but costs/person were marginal.
Conclusions:  Community water fluoridation remains a cost-effective preventive measure in Australia.  相似文献   
70.
Acute spinal cord injury: MR imaging at 1.5 T   总被引:19,自引:0,他引:19  
Thirty-seven magnetic resonance (MR) imaging studies were performed with a 1.5-T magnet and surface coils in 27 patients with suspected spinal cord injuries. Imaging was performed 1 day to 6 weeks after injury. Cord abnormalities were seen with MR in 19 patients, while skeletal and/or ligamentous injuries were seen in 21 (78%). Three types of MR signal patterns were seen in association with cord injuries. Acute intraspinal hemorrhage was seen in five patients with cord injuries and demonstrated decreased signal intensity on T2-weighted images obtained within 24 hours of injury. Cord edema and contusion had high signal intensity on T2-weighted images and were observed in 12 cases with cord injury. Neurologic recovery, determined in 16 patients, was insignificant in patients with intraspinal hemorrhage; however, patients with cord edema or contusion recovered significant neurologic function. MR at 1.5 T is extremely useful in the diagnosis of acute cord injury and also demonstrates potential in predicting neurologic recovery.  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