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   147954篇
  免费   13935篇
  国内免费   4022篇
耳鼻咽喉   990篇
儿科学   3454篇
妇产科学   2310篇
基础医学   25424篇
口腔科学   3576篇
临床医学   10158篇
内科学   24437篇
皮肤病学   2485篇
神经病学   14582篇
特种医学   4410篇
外国民族医学   29篇
外科学   14109篇
综合类   13176篇
现状与发展   17篇
预防医学   8639篇
眼科学   1558篇
药学   20069篇
  41篇
中国医学   4811篇
肿瘤学   11636篇
  2023年   2211篇
  2022年   5196篇
  2021年   6287篇
  2020年   5248篇
  2019年   6603篇
  2018年   6296篇
  2017年   5593篇
  2016年   4976篇
  2015年   5515篇
  2014年   8311篇
  2013年   8883篇
  2012年   7277篇
  2011年   8491篇
  2010年   6880篇
  2009年   6952篇
  2008年   6853篇
  2007年   5947篇
  2006年   5231篇
  2005年   4715篇
  2004年   4070篇
  2003年   3709篇
  2002年   2763篇
  2001年   2425篇
  2000年   2077篇
  1999年   1938篇
  1998年   1776篇
  1997年   1728篇
  1996年   1584篇
  1995年   1415篇
  1994年   1291篇
  1993年   1185篇
  1992年   956篇
  1991年   866篇
  1990年   725篇
  1989年   631篇
  1988年   616篇
  1986年   675篇
  1985年   1782篇
  1984年   2516篇
  1983年   1690篇
  1982年   1784篇
  1981年   1668篇
  1980年   1426篇
  1979年   1241篇
  1978年   1042篇
  1977年   887篇
  1976年   1009篇
  1975年   689篇
  1974年   597篇
  1973年   623篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
61.
62.
ObjectiveThe purpose of this paper is to review the efficacy and safety profile in children treated with topical 0.03% Tacrolimus ointment for vernal keratoconjunctivitis in Middle East and to propose a treatment posology. According to recent studies, a complex non-IgE dependent mechanism plays a relevant role in the pathogenesis of vernal keratoconjunctivitis. Numerous cells and mediators have been found in the serum, conjunctiva and tears of patients with Vernal keratoconjunctivitis.DesignThis case series included 10 patients from a single centre, pediatric department of a tertiary hospital with active symptomatic vernal keratoconjunctivitis. All the patients had proliferative lesions and corneal involvement despite conventional medications, including topical steroids. All other medications, systemic and topical: steroids, antihistamines and cyclosporine, were unsuccessful. Patients were treated with topical 0.03% Tacrolimus ointment twice daily for 8 weeks and then once a day for the next two month followed by thrice a week for two months. The changes in symptoms and signs after treatment were evaluated, also the development of possible complications was assessed.ResultsThe results showed a significant reduction in signs and symptoms after 4 weeks of the treatment. Clinical resolution of giant papillae and corneal lesions were seen within eight weeks and no additional drug was required during that period, except tear substitutes. Treatment was continued for period of two months and then slowly reduced.ConclusionThe use of 0.03% Tacrolimus ointment is safe and effective in children refractory to conventional treatment of vernal keratoconjunctivitis even in high temperature climate as Middle East. Due to the effectiveness of the treatment, the dosage used may be proposed for conventional use.  相似文献   
63.
64.
BackgroundUnequal housing access resulted in more than 150 million homeless people worldwide, with millions more expected to be added every year due to the ongoing climate-related crises. Homeless population has a counterproductive effect on the social, psychological integration efforts by the community and exposure to other severe health-related issues. Geographic Information Systems (GIS) have long been applied in urban planning and policy, housing and homelessness, and health-related research.MethodsWe used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method to systematically review 24 articles collected from multiple databases (n = 10) that focused on health-related issues among homeless people and used geospatial analysis techniques in their research.ResultsOur findings indicated a geographic clustering of case study locations– 26 out of the 31 case study sites are from the USA and Canada. Studies used spatial analysis techniques to identify hotspots, clusters and patterns of patient location and population distribution. Studies also reported relationships among the location of homeless shelters and substance use, discarded needles, different infectious and non-infectious disease clusters.ConclusionMost studies were restricted in analyzing and visualizing the patterns and disease clusters; however, geospatial analyses techniques are useful and offer diverse techniques for a more sophisticated understanding of the spatial characteristics of the health issues among homeless people. Better integration of GIS in health research among the homeless would help formulate sensible policies to counter health inequities among this vulnerable population group.  相似文献   
65.
IntroductionSunlight exposure is the main source of vitamin D. Our aim was to describe both sun exposure and sun protection behaviour in a series of patients with inflammatory bowel disease (IBD), and to study their potential association with vitamin D concentration.Patients and methodsA cross sectional, observational study. The clinical-demographic variables were obtained via clinical interviews and medical history review. The sunlight exposure assessment was carried out using the Sun Exposure Questionnaire and the concentration of 25-hydroxy vitamin D (25OHD) was measured by an electro-chemiluminescence immunoassay. Questionnaires were conducted on quality of life, physical activity, weekly vitamin D intake and sun protection behaviour.Results149 patients were included. In 69% of patients, deficient or insufficient 25OHD values were recorded. 67% showed low sun exposure. A modest significant correlation was observed between the total score of the solar exposure questionnaire and the 25OHD concentration in the complete series (r = 0.226, P = .006) and in the summer (r = 0.274, P = .01). The sun protection behaviour questionnaire score did not influence the 25OHD concentration. In the multivariate analysis, only the presence of clinical activity was associated with low sun exposure (OR = 3.23).DiscussionSun exposure according to the questionnaire used was low, was associated with the presence of clinical activity and was weakly correlated with serum 25OHD concentration. More studies are needed to explore the use of individual questionnaires for sun exposure and its relationship with vitamin D in patients with IBD.  相似文献   
66.
67.
68.
69.
A pulmonary artery (PA) sling is a very rare congenital cardiovascular anomaly, and only a few studies have reported PA slings in fetuses. The relationship of the PA, aorta, ductus arteriosus, and trachea can be evaluated in the 3‐vessel and 3‐vessel and trachea views during fetal echocardiography. A PA sling can be detected by abnormal positioning of the left PA in relation to the trachea when sweeping from the 3‐vessel view cranially to the 3‐vessel and trachea view. Here we report 3 cases of fetal PA slings and their follow‐ups. Two cases were confirmed by postnatal echocardiography, and the other case was confirmed by a cardiovascular cast after pregnancy termination. We emphasize that the 3‐vessel and 3‐vessel and trachea views are of crucial importance in the prenatal diagnosis of a PA sling.  相似文献   
70.
目的通过线性法测量皮质下缺血性血管病(SIVD)患者脑萎缩,分析其与认知功能损害的相关性。方法共纳入SIVD组50例,健康对照组50例。所有入组对象均完成一般情况评定、Mo CA量表评估认知功能、头颅MRI检查,线性法进行脑萎缩测量。结果 SIVD组代表脑室系统横径的测量值及脑沟测量值,除桥池宽度外,均较对照组显著增大(P 0. 05)。SIVD组的脑萎缩测量相对值除脑干指数外,均显著高于对照组(P 0. 05)。SIVD组双侧侧脑室两额角间最宽距离、双侧侧脑室额角两侧尾状核头间最小距离、第三脑室宽度、双侧侧脑室腰部外侧壁最小距离与Mo CA评分呈显著负相关(P 0. 05)。SIVD组脑萎缩测量相对值中的额角指数、尾状核指数、哈氏值、第三脑室宽度与视空间能力、计算力、延迟记忆和定向力均呈负相关(P 0. 05)。结论 SIVD患者存在明显的皮质和皮质下萎缩,并与认知功能损害相关。哈氏值、额角指数、尾状核指数、第三脑室宽度可作为SIVD患者脑萎缩的预测指标,提示执行功能/视空间及计算力、记忆力的损害。  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