收费全文 | 2374篇 |
免费 | 204篇 |
国内免费 | 12篇 |
耳鼻咽喉 | 31篇 |
儿科学 | 39篇 |
妇产科学 | 29篇 |
基础医学 | 430篇 |
口腔科学 | 130篇 |
临床医学 | 223篇 |
内科学 | 499篇 |
皮肤病学 | 72篇 |
神经病学 | 103篇 |
特种医学 | 74篇 |
外科学 | 267篇 |
综合类 | 59篇 |
预防医学 | 151篇 |
眼科学 | 32篇 |
药学 | 221篇 |
中国医学 | 2篇 |
肿瘤学 | 228篇 |
2023年 | 21篇 |
2022年 | 19篇 |
2021年 | 26篇 |
2020年 | 32篇 |
2019年 | 33篇 |
2018年 | 48篇 |
2017年 | 42篇 |
2016年 | 47篇 |
2015年 | 45篇 |
2014年 | 54篇 |
2013年 | 95篇 |
2012年 | 90篇 |
2011年 | 111篇 |
2010年 | 68篇 |
2009年 | 75篇 |
2008年 | 90篇 |
2007年 | 101篇 |
2006年 | 81篇 |
2005年 | 98篇 |
2004年 | 71篇 |
2003年 | 95篇 |
2002年 | 75篇 |
2001年 | 78篇 |
2000年 | 81篇 |
1999年 | 72篇 |
1998年 | 43篇 |
1997年 | 54篇 |
1996年 | 33篇 |
1995年 | 32篇 |
1994年 | 24篇 |
1993年 | 21篇 |
1992年 | 48篇 |
1991年 | 54篇 |
1990年 | 35篇 |
1989年 | 52篇 |
1988年 | 63篇 |
1987年 | 51篇 |
1986年 | 42篇 |
1985年 | 36篇 |
1984年 | 33篇 |
1983年 | 39篇 |
1982年 | 34篇 |
1981年 | 18篇 |
1979年 | 15篇 |
1978年 | 22篇 |
1977年 | 20篇 |
1976年 | 22篇 |
1975年 | 22篇 |
1974年 | 20篇 |
1972年 | 14篇 |
Background
Breast-feeding may affect the risk of developing allergy during childhood and may also cause exposure to immunotoxicants, such as polychlorinated biphenyls (PCBs), which are of concern as marine pollutants in the Faroe Islands and the Arctic region.Objectives
The objective was to assess whether sensitization and development of allergic disease is associated with duration of breast-feeding and prenatal or postnatal exposures to PCBs and methylmercury.Methods
A cohort of 656 singleton births was formed in the Faroe Islands during 1999–2001. Duration of breast-feeding and history of asthma and atopic dermatitis were recorded at clinical examinations at 5 and 7 years of age. PCB and mercury concentrations were determined in blood samples obtained at parturition and at follow-up. Serum from 464 children (71%) at 7 years of age was analyzed for total immunoglobulin E (IgE) and grass-specific IgE.Results
The total IgE concentration in serum at 7 years of age was positively associated both with the concomitant serum PCB concentration and with the duration of breast-feeding. However, the effect only of the latter was substantially attenuated in a multivariate analysis. A raised grass-specific IgE concentration compatible with sensitization was positively associated with the duration of breast-feeding and inversely associated with prenatal methylmercury exposure. However, a history of asthma or atopic dermatitis was not associated with the duration of breast-feeding, although children with atopic dermatitis had lower prenatal PCB exposures than did nonallergic children.Conclusions
These findings suggest that developmental exposure to immunotoxicants may both increase and decrease the risk of allergic disease and that associations between breast-feeding and subsequent allergic disease in children may, at least in part, reflect lactational exposure to immunotoxic food contaminants. 相似文献![点击此处可从《European journal of heart failure》网站下载免费的PDF全文](/ch/ext_images/free.gif)
![点击此处可从《Internal medicine journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Background
The EVOLVE (evaluating evidence, enhancing efficiencies) initiative aims to drive safer, higher‐quality patient care through identifying and reducing low‐value practices.Aims
To determine the Australian Rheumatology Association’s (ARA) ‘top five’ list of low‐value practices.Methods
A working group comprising 19 rheumatologists and three trainees compiled a preliminary list. Items were retained if there was strong evidence of low value and there was high or increasing clinical use and/or increasing cost. All ARA members (356 rheumatologists and 72 trainees) were invited to indicate their ‘top five’ list from a list of 12‐items through SurveyMonkey in December 2015 (reminder February 2016).Results
A total of 179 rheumatologists (50.3%) and 19 trainees (26.4%) responded. The top five list (percentage of rheumatologists, including item in their top five list) was: Do not perform arthroscopy with lavage and/or debridement for symptomatic osteoarthritis of the knee nor partial meniscectomy for a degenerate meniscal tear (73.2%); Do not order anti‐nuclear antibody (ANA) testing without symptoms and/or signs suggestive of a systemic rheumatic disease (56.4%); Do not undertake imaging for low back pain for patients without indications of an underlying serious condition (50.8%); Do not use ultrasound guidance to perform injections into the subacromial space as it provides no additional benefit in comparison to landmark‐guided injection (50.3%) and Do not order anti‐double‐stranded DNA antibodies in ANA negative patients unless the clinical suspicion of systemic lupus erythematosus remains high (45.3%).Conclusions
This list is intended to increase awareness among rheumatologists, other clinicians and patients about commonly used low‐value practices that should be questioned. 相似文献Cerebral mitochondrial dysfunction is prominent in the pathophysiology of severe bacterial meningitis. In the present study, we hypothesize that the metabolic changes seen after intracisternal lipopolysaccharide (LPS) injection in a piglet model of meningitis is compatible with mitochondrial dysfunction and resembles the metabolic patterns seen in patients with bacterial meningitis.
MethodsEight pigs received LPS injection in cisterna magna, and four pigs received NaCl in cisterna magna as a control. Biochemical variables related to energy metabolism were monitored by intracerebral microdialysis technique and included interstitial glucose, lactate, pyruvate, glutamate, and glycerol. The intracranial pressure (ICP) and brain tissue oxygen tension (PbtO2) were also monitored along with physiological variables including mean arterial pressure, blood glucose, lactate, and partial pressure of O2 and CO2. Pigs were monitored for 60 min at baseline and 240 min after LPS/NaCl injection.
ResultsAfter LPS injection, a significant increase in cerebral lactate/pyruvate ratio (LPR) compared to control group was registered (p = 0.01). This increase was due to a significant increased lactate with stable and normal values of pyruvate. No significant change in PbtO2 or ICP was registered. No changes in physiological variables were observed.
ConclusionsThe metabolic changes after intracisternal LPS injection is compatible with disturbance in the oxidative metabolism and partly due to mitochondrial dysfunction with increasing cerebral LPR due to increased lactate and normal pyruvate, PbtO2, and ICP. The metabolic pattern resembles the one observed in patients with bacterial meningitis. Metabolic monitoring in these patients is feasible to monitor for cerebral metabolic derangements otherwise missed by conventional intensive care monitoring.
相似文献