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   409篇
  免费   39篇
耳鼻咽喉   18篇
儿科学   7篇
妇产科学   4篇
基础医学   69篇
口腔科学   10篇
临床医学   32篇
内科学   89篇
皮肤病学   3篇
神经病学   46篇
特种医学   7篇
外科学   41篇
综合类   1篇
一般理论   1篇
预防医学   24篇
眼科学   5篇
药学   70篇
肿瘤学   21篇
  2023年   5篇
  2022年   7篇
  2021年   16篇
  2020年   5篇
  2019年   5篇
  2018年   13篇
  2017年   2篇
  2016年   6篇
  2015年   11篇
  2014年   9篇
  2013年   10篇
  2012年   19篇
  2011年   22篇
  2010年   11篇
  2009年   14篇
  2008年   24篇
  2007年   20篇
  2006年   28篇
  2005年   27篇
  2004年   21篇
  2003年   31篇
  2002年   22篇
  2001年   7篇
  2000年   3篇
  1999年   6篇
  1998年   10篇
  1997年   3篇
  1996年   4篇
  1995年   3篇
  1994年   8篇
  1993年   4篇
  1992年   12篇
  1991年   14篇
  1990年   14篇
  1989年   12篇
  1988年   2篇
  1987年   1篇
  1986年   4篇
  1985年   3篇
  1984年   2篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1977年   2篇
  1968年   1篇
  1966年   1篇
排序方式: 共有448条查询结果,搜索用时 15 毫秒
371.
The goal of this study was to evaluate the impact of Mexico's conditional cash transfer program, Oportunidades, on the growth of children <24 mo of age living in urban areas. Beneficiary families received cash transfers, a fortified food (targeted to pregnant and lactating women, children 6-23 mo, and children with low weight 2-4 y), and curative health services, among other benefits. Program benefits were conditional on preventative health care utilization and attendance of health and nutrition education sessions. We estimated the impact of the program after 2 y of operation in a panel of 432 children <24 mo of age at baseline (2002). We used difference-in-difference propensity score matching, which takes into account nonrandom program participation and the effects of unobserved fixed characteristics on outcomes. All models controlled for child age, sex, baseline anthropometry, and maternal height. Anthropometric Z-scores were calculated using the new WHO growth reference standards. There was no overall association between program participation and growth in children 6 to 24 mo of age. Children in intervention families younger than 6 mo of age at baseline grew 1.5 cm (P < 0.05) more than children in comparison families, corresponding to 0.41 height-for-age Z-scores (HAZ) (P < 0.05). They also gained an additional 0.76 kg (P < 0.01) or 0.47 weight-for-height Z-scores (P < 0.05). Children living in the poorest intervention households tended (0.05 < P < 0.10) to be taller than comparison children (0.9 cm, 0.27 HAZ). Oportunidades, with its strong nutrition component, is an effective tool to improve the growth of infants in poor urban households.  相似文献   
372.
373.
Evidence on the cost‐effectiveness of multisectoral maternal and child health and nutrition programmes is scarce. We conducted a prospective costing study of two food‐assisted maternal and child health and nutrition programmes targeted to pregnant women and children during the first 1,000 days (pregnancy to 2 years). Each was paired with a cluster‐randomized controlled trial to evaluate impact and compare the optimal quantity and composition of food rations (Guatemala, five treatment arms) and their optimal timing and duration (Burundi, three treatment arms). We calculated the total and per beneficiary cost, conducted cost consequence analyses, and estimated the cost savings from extending the programme for 2 years. In Guatemala, the programme model with the lowest cost per percentage point reduction in stunting provided the full‐size family ration with an individual ration of corn–soy blend or micronutrient powder. Reducing family ration size lowered costs but failed to reduce stunting. In Burundi, providing food assistance for the full 1,000 days led to the lowest cost per percentage point reduction in stunting. Reducing the duration of ration eligibility reduced per beneficiary costs but was less effective. A 2‐year extension could have saved 11% per beneficiary in Guatemala and 18% in Burundi. We found that investments in multisectoral nutrition programmes do not scale linearly. Programmes providing smaller rations or rations for shorter durations, although less expensive per beneficiary, may not provide the necessary dose to improve (biological) outcomes. Lastly, delivering effective programmes for longer periods can generate cost savings by dispersing start‐up costs and lengthening peak operating capacity.  相似文献   
374.
375.
From 2000 to 2005, we investigated prospectively 98 cases of imported non-Plasmodium falciparum malaria (48 Plasmodium vivax, 34 P. ovale, and 16 P. malariae). Latency period between return and clinical attack exceeded three months in 40% of the patients. It was longer in travelers who had taken chemoprophylaxis. Time to diagnosis was longer in patients with P. malariae infection and in those with late-onset first attack. Parasite density was often lower than 500/microL, especially in P. ovale malaria. Relapses were diagnosed in 18% of all malaria episodes. Eight (17%) P. vivax and 2 (6%) P. ovale malaria episodes were due to relapse despite standard primaquine therapy. Diagnosis of imported non-falciparum malaria is often challenged by long latency period and low parasite density. In addition, the substantial relapse rate despite standard primaquine therapy supports the use of a higher dose of primaquine to eradicate P. vivax and P. ovale malaria effectively.  相似文献   
376.
Etiology and outcome of fever after a stay in the tropics   总被引:2,自引:0,他引:2  
BACKGROUND: Information on epidemiology and prognosis of imported fever is scarce and almost exclusively limited to hospital settings. METHODS: From 2000 to 2005, all travelers presenting at our referral outpatient and inpatient centers with ongoing fever within 12 months after a stay in the tropics were prospectively followed. Case definitions and treatment were based on international recommendations. Outcome was assessed by at least 1 follow-up consultation or telephone call within 3 months after initial contact. RESULTS: A total of 1842 fever episodes were included, involving 1743 patients. Regions of exposure were mainly sub-Saharan Africa (68%) and the Southeast Asia-Pacific region (12%). Tropical diseases accounted for 39% of all cases and cosmopolitan infections for 34%. Diagnosis often remained unknown (24%). The pattern of tropical diseases was mainly influenced by the travel destination, with malaria (35%, mainly Plasmodium falciparum) and rickettsial infection (4%) as the leading diagnoses after a stay in Africa; dengue (12%), malaria (9%), and enteric fever (4%) after travel to Asia; and dengue (8%) and malaria (4%) on return from Latin America. Disease pattern varied also according to the category of travelers, the delay between exposure and fever onset, and the setting. Hospitalization was required for 503 fever episodes (27%). Plasmodium falciparum malaria accounted for 36% of all admissions and was the only tropical cause of death (5 of 9 patients). Fever of unknown cause had invariably a favorable outcome. CONCLUSION: The clinical spectrum of imported fever is highly destination specific but also depends on other factors. Plasmodium falciparum malaria was the leading cause of mortality in the study population.  相似文献   
377.
Differential diagnosis of fever in travelers returning from the tropics is extremely diverse. Apart from the travel destination, other diagnostic predictors of tropical infections are poorly documented in returning travelers. From April 2000 to December 2005, we prospectively enrolled all patients presenting at our referral centers with fever within 1 year after visiting a tropical or subtropical area. For clinical relevance, the diagnostic predictors of the leading tropical conditions were particularly investigated in the febrile episodes occurring during travel or within 1 month after return (defined as early-onset fever). In total, 2071 fever episodes were included, occurring in 1962 patients. Most patients were western travelers (60%) or expatriates (15%). Regions of exposure were mainly sub-Saharan Africa (68%) and southern Asia/Pacific (14%). Early-onset fever accounted for 1619 episodes (78%). Most tropical infections were related to specific travel destinations. Malaria (mainly Plasmodium falciparum) was strongly predicted by the following features: enlarged spleen, thrombocytopenia (platelet count <150 x 10(3)/microL), fever without localizing symptoms, and hyperbilirubinemia (total bilirubin level >or=1.3 mg/dL). When malaria had been ruled out, main predictors were skin rash and skin ulcer for rickettsial infection (mainly African tick bite fever); skin rash, thrombocytopenia, and leukopenia (leukocyte count <4 x 10(3)/microL) for dengue; eosinophil count >or=0.5 x 10(3)/microL for acute schistosomiasis; and enlarged spleen and elevated alanine aminotransferase level (>or=70 IU/L) for enteric fever. The initial clinical and laboratory assessment can help in selecting appropriate investigations and empiric treatments for patients with imported fever.  相似文献   
378.
The resilience of the human skin is mediated by elastic fibres mainly consisting of fibrillins and elastin. In order to establish a model system to study the impact of cosmetic and pharmaceutical compounds on the elastic system in vitro, we analyzed the expression of elastin in a newly developed full-thickness skin model. After a 5-week cultivation period the skin model developed a fully differentiated epidermis including a stratum corneum. The dermis contains fibroblasts embedded in extracellular matrix proteins. The models were viable until at least 51 days at the air-liquid interface (ALI) culture. Using immunohistochemistry we detected elastin first on day 7 of ALI. With proceeding culture time, elastin-positive fibres of different lengths and distribution patterns accumulated in the dermal compartment. Elastin mRNA expression started on day 7 of ALI, increased until day 10 and then dropped to a level comparable to that of day 7. Our results demonstrate that in our full-thickness skin model an in vivo-like elastic system, which clearly mimics at least two subsets of dermal elastic fibres, is generated. This physiological property favours the model as a promising animal-free approach to study those processes leading to an environment- and age-dependent decrease in skin elasticity.  相似文献   
379.
380.
The organisation of health care is rapidly changing. There is a trend to move away from individual health care institutions towards transmural integrated care and interorganizational collaboration in networks. However, within such collaboration and network there is often likely to be a pluralism of values as different health care institutions often have very different values. For this paper, we examine three different models of how we believe institutions can come to collaborate in networks, and thus reap the potential benefits of such collaboration, despite having different moral beliefs or values. A first way is the pragmatic way in which the different health care institutions avoid ethical reflection and focus on solutions. A second possible route is that of consensus where health care institutions base their collaboration on values that they all share. The third, and final, approach is that of compromise. Although moral compromise is often seen in a negative light, we argue that in many cases compromise might be necessary and ethically justified. In a final section, we will shift our focus from discussing various theoretical methods to allow collaboration to the potential content of consensus or compromise.  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