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   654篇
  免费   43篇
  国内免费   16篇
耳鼻咽喉   2篇
儿科学   42篇
妇产科学   2篇
基础医学   48篇
口腔科学   8篇
临床医学   64篇
内科学   143篇
皮肤病学   6篇
神经病学   13篇
特种医学   228篇
外科学   39篇
综合类   32篇
预防医学   46篇
眼科学   4篇
药学   13篇
中国医学   1篇
肿瘤学   22篇
  2022年   2篇
  2021年   8篇
  2020年   7篇
  2019年   1篇
  2018年   7篇
  2017年   6篇
  2016年   10篇
  2015年   8篇
  2014年   5篇
  2013年   15篇
  2012年   7篇
  2011年   11篇
  2010年   19篇
  2009年   27篇
  2008年   10篇
  2007年   15篇
  2006年   11篇
  2005年   14篇
  2004年   5篇
  2003年   23篇
  2002年   13篇
  2001年   6篇
  2000年   4篇
  1999年   12篇
  1998年   47篇
  1997年   48篇
  1996年   38篇
  1995年   22篇
  1994年   40篇
  1993年   25篇
  1992年   6篇
  1991年   12篇
  1990年   8篇
  1989年   28篇
  1988年   20篇
  1987年   18篇
  1986年   25篇
  1985年   14篇
  1984年   16篇
  1983年   12篇
  1982年   13篇
  1981年   24篇
  1980年   6篇
  1979年   5篇
  1978年   9篇
  1977年   10篇
  1976年   11篇
  1975年   10篇
排序方式: 共有713条查询结果,搜索用时 15 毫秒
51.
52.

Objective

To compare oxygen supply options for health facilities in the Gambia and develop a decision-making algorithm for choosing oxygen delivery systems in Africa and the rest of the developing world.

Methods

Oxygen cylinders and concentrators were compared in terms of functionality and cost. Interviews with key informants using locally developed and adapted WHO instruments, operational assessments, cost-modelling and cost measurements were undertaken to determine whether oxygen cylinders or concentrators were the better choice. An algorithm and a software tool to guide the choice of oxygen delivery system were constructed.

Findings

In the Gambia, oxygen concentrators have significant advantages compared to cylinders where power is reliable; in other settings, cylinders are preferable as long as transporting them is feasible. Cylinder costs are greatly influenced by leakage, which is common, whereas concentrator costs are affected by the cost of power far more than by capital costs. Only two of 12 facilities in the Gambia were found suitable for concentrators; at the remaining 10 facilities, cylinders were the better option.

Conclusion

Neither concentrators nor cylinders are well suited to every situation, but a simple options assessment can determine which is better in each setting. Nationally this would result in improved supply and lower costs by comparison with conventional cylinders alone, although ensuring a reliable supply would remain a challenge. The decision algorithm and software tool designed for the Gambia could be applied in other developing countries.  相似文献   
53.

Background  

Cholera remains a serious public health problem in low-income countries despite efforts in the past to promote oral rehydration therapy as major treatment. In 2007, the majority of worldwide cases (94%) and deaths (99%) were reported from Africa. To improve cholera control efforts in addition to maintaining and improving existing water supply, sanitation and hygiene behaviour measures, the World Health Organization has recently started to consider the use of vaccines as an additional public health tool. To assess this new approach in endemic settings, a project was launched in Zanzibar to vaccinate 50,000 individuals living in communities at high risk of cholera with an oral two-dose vaccine (Dukoral?).  相似文献   
54.
The aim of the study was to determine if high-dose bovine surfactant (Alveofact, initially 100 mg/kg birth weight) would improve oxygenation compared with low-dose surfactant (50 mg/kg birth weight) administered intratracheally within 1 h after birth. Inclusion criteria included gestational age 24–29 weeks and birth weight 500–1500 g, intubation and mechanical ventilation, absence of congenital malformations and bacterial infections. Retreatment was considered if the fraction of inspired oxygen (FiO2) was > 0.4 (dose 50 mg/kg birth weight). The primary endpoint was level of oxygenation (PaO2/ FiO2) 2 h after treatment. The study design was a sequential analysis using a triangular test with alpha = 0.05 and 95% power to detect a 25 % improvement in the endpoint. Oxygenation was improved significantly with high-dose ( n = 42) compared to low-dose treatment ( n =48): 30.9±15.0 kPa (231.5±112.7 mmHg) versus 24.1±15.7 kPa (180.6±118.0 mmHg) (mean ± SD). The survival rate was 83% in both groups and the incidence of pulmonary interstitial emphysema was 33% versus 14% with the high-dose treatment. We conclude that high-dose surfactant significantly improved oxygenation and reduced lung barotrauma. An initial dose greater than 50 mg/kg birth weight of surfactant is required for optimal acute response.  相似文献   
55.
Breast milk samples from three groups of Brazilian women were evaluated: G1, mothers delivering term babies of low birth weight (n=16); G2, mothers delivering preterm babies of appropriate birth weight (n = 20); G3, mothers delivering term babies of appropriate birth weight ( n = 30). Milk samples were obtained at 48 h and on the 7th, 15th, 30th and 60th days after delivery and they were analyzed for lysozyme and total IgA levels and for the presence of specific antibodies against Poliovirus types I, II, III, Rotavirus, Herpes simplex virus, Varicella zoster and Cytomegalovirus. The groups were not statistically different in relation to mother's age, parity, type of delivery or socio-economic levels. IgA levels were higher in both low-birth-weight groups (G1 & G2) compared to the control group (G3) throughout the study period. Lysozyme levels decreased up to the 15th day, increasing thereafter up to the 60th day in all groups. Specific antibodies were detected throughout the study period, with no differences among groups. We conclude that breast milk composition of mothers delivering low-birth-weight babies (G1 & G2) was similar despite the different gestational ages.  相似文献   
56.
57.
In a previous report the effectiveness of intraperitoneal bupivacaine in reducing pain following laparoscopic cholecystectomy was demonstrated. Other methods of pain relief are commonly used but none has been compared following laparoscopic cholecystectomy. In two further studies we have compared the analgesic effect of intraperitoneal bupivacaine against wound infiltration with bupivacaine, and against intraperitoneal bupivacaine with the addition of a non-steroidal anti-inflammatory drug (NSAID) in patients undergoing laparoscopic cholecystectomy. Two consecutive studies were performed. In the first, patients in group 1 were given 20 ml of 0.25% bupivacaine into the peritoneal cavity; patients in group 2 were given 20 ml of 0.25% bupivacaine injected into the trocar wounds. In the second study, patients in group 1 were given 20 ml of 0.25% bupivacaine into the peritoneal cavity; patients in group 2 were given 20 ml of 0.25% bupivacaine into the peritoneal cavity and a diclofenac suppository (100 mg) one hour before surgery. Postoperative pain was assessed with a visual analogue pain scale. There was no difference in pain scores in the two groups in either study. Intraperitoneal bupivacaine is as effective as wound infiltration. The addition of an NSAID makes no difference in the reduction of postoperative pain following laparoscopic cholecystectomy.  相似文献   
58.
59.
60.
A 3 year old Turkish girl is described who was suffering from major histocompatibility complex (MHC) class II deficiency syndrome, which is characterised by the lack of expression of HLA class II antigens on mononuclear cells. The presence of HLA class II genes was demonstrable at the DNA level. Combined immunodeficiency was indicated by hypogammaglobulinaemia and the absence of delayed type hypersensitivity on skin testing. Further, she was unable to produce specific antibodies towards foreign antigens and suffered from recurrent pulmonary, gastrointestinal, and septic infections from the third month of life. The clinical course was complicated by a Coombs test positive haemolytic anaemia due to the production of autoantibodies against the rhesus "e' antigen, a non-glycosylated protein antigen. Haemolysis could be controlled by oral steroid treatment. This case is of interest as it shows that despite the absence of HLA class II antigens and combined immunodeficiency autoimmune reactions with production of specific autoantibodies directed to protein antigens are possible.  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