全文获取类型
收费全文 | 57014篇 |
免费 | 3601篇 |
国内免费 | 1182篇 |
专业分类
耳鼻咽喉 | 135篇 |
儿科学 | 692篇 |
妇产科学 | 965篇 |
基础医学 | 7388篇 |
口腔科学 | 1453篇 |
临床医学 | 5653篇 |
内科学 | 6859篇 |
皮肤病学 | 2087篇 |
神经病学 | 6661篇 |
特种医学 | 1112篇 |
外科学 | 5065篇 |
综合类 | 4972篇 |
现状与发展 | 2篇 |
一般理论 | 1篇 |
预防医学 | 8342篇 |
眼科学 | 607篇 |
药学 | 6305篇 |
38篇 | |
中国医学 | 2198篇 |
肿瘤学 | 1262篇 |
出版年
2025年 | 67篇 |
2024年 | 1082篇 |
2023年 | 1191篇 |
2022年 | 1968篇 |
2021年 | 2541篇 |
2020年 | 2561篇 |
2019年 | 2216篇 |
2018年 | 2030篇 |
2017年 | 2295篇 |
2016年 | 2430篇 |
2015年 | 2279篇 |
2014年 | 3317篇 |
2013年 | 4994篇 |
2012年 | 2733篇 |
2011年 | 3186篇 |
2010年 | 2496篇 |
2009年 | 2618篇 |
2008年 | 2719篇 |
2007年 | 2311篇 |
2006年 | 2196篇 |
2005年 | 1711篇 |
2004年 | 1590篇 |
2003年 | 1382篇 |
2002年 | 1119篇 |
2001年 | 1049篇 |
2000年 | 818篇 |
1999年 | 710篇 |
1998年 | 736篇 |
1997年 | 661篇 |
1996年 | 628篇 |
1995年 | 484篇 |
1994年 | 430篇 |
1993年 | 347篇 |
1992年 | 403篇 |
1991年 | 364篇 |
1990年 | 304篇 |
1989年 | 304篇 |
1988年 | 258篇 |
1987年 | 174篇 |
1986年 | 178篇 |
1985年 | 189篇 |
1984年 | 157篇 |
1983年 | 97篇 |
1982年 | 104篇 |
1981年 | 78篇 |
1980年 | 77篇 |
1979年 | 65篇 |
1978年 | 48篇 |
1977年 | 32篇 |
1976年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Stress Testing Versus CT Angiography in Patients With Diabetes and Suspected Coronary Artery Disease
Abhinav Sharma Adrian Coles Nishant K. Sekaran Neha J. Pagidipati Michael T. Lu Daniel B. Mark Kerry L. Lee Hussein R. Al-Khalidi Udo Hoffmann Pamela S. Douglas 《Journal of the American College of Cardiology》2019,73(8):893-902
Background
The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.Objectives
The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.Methods
PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.Results
Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).Conclusions
In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550) 相似文献2.
B. Tutluolu S. At A. N. Anakkaya E. Altu G. A. Tosun M. Yaman 《Clinical and experimental allergy》2002,32(8):1170-1173
OBJECTIVE: This study aimed to investigate the rate of occupational sensitization to horse hair in grooms and whether occupational exposure to horse hair increases respiratory and allergic symptoms and affects lung function in grooms or not. METHODS: This is a cross-sectional study. Two hundred grooms were randomly selected among 1000 grooms working in Veliefendi Hippodrome of Istanbul. One hundred and twenty-five subjects agreed to enter the study. Ninety-two workers who worked in the different parts of this hippodrome enrolled as the control group. A detailed questionnaire including respiratory and allergic symptoms was filled in, physical examination, skin prick tests and pulmonary function tests were performed. RESULTS: Sensitization to horse hair was 12.8% in grooms and 4.3% in controls. The difference was statistically significant (P = 0.0035). Asthma was found in 14.4% of the grooms and 5.4% of the controls, allergic rhinitis in 42.4% of the grooms and 18.4% of the controls, allergic conjunctivitis in 35.2% of the grooms and 15.2% of the controls, and allergic skin diseases in 32.8% of the grooms and 13% of the controls. The differences were statistically significant (P = 0.043, P = 0.0002, P = 0.001 and P = 0.0008, respectively). The means of FEV1, FEV1/FVC and FVC parameters were significantly lower in the groom group (P = 0.006, P = 0.001 and P = 0.003, respectively). In the multivariate analysis, being in the groom group and working years were found to be predictive factors for impairments of lung function (P < 0.001 and P = 0.002, respectively). CONCLUSION: Occupational exposure to horse increases the sensitization to horse hair, induces asthma and allergic symptoms and also impairs lung functions. 相似文献
3.
Design and conduct of occupational epidemiology studies: III. Design aspects of case-control studies
Currently available approaches for the design of occupational case-control studies are reviewed. An accompanying paper reviews methods of analysis. We commence by drawing a distinction between cohort-based and registry-based studies. Methods for selecting cases and controls are then reviewed, including cumulative incidence and incidence density sampling, matching, sources of controls, and issues in control selection. Finally, the advantages and disadvantages of the case-control approach are summarized. 相似文献
4.
R. Marfella F. Cacciapuoti M. Siniscalchi F. C. Sasso F. Marchese F. Cinone E. Musacchio M. A. Marfella L. Ruggiero G. Chiorazzo D. Liberti G. Chiorazzo G. F. Nicoletti C. Saron F. D’Andrea C. Ammendola M. Verza L. Coppola 《Diabetic medicine》2006,23(9):974-981
Background Oxidative stress and increased inflammation have been reported to be increased in subjects with diabetes and to be involved in the pathogenesis of cardiovascular complications after myocardial infarction (MI). It is well recognized that red wine has antioxidant and anti‐inflammatory activities. We examined the effects of moderate red wine intake on echocardiographic parameters of functional cardiac outcome in addition to inflammatory cytokines and nitrotyrosine (oxidative stress marker), in subjects with diabetes after a first uncomplicated MI. Methods One hundred and fifteen subjects with diabetes who had sustained a first non‐fatal MI were randomized to receive a moderate daily amount of red wine (intervention group) or not (control group). Echocardiographic parameters of ventricular dys‐synchrony, circulating levels of nitrotyrosine, tumour necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6), interleukin‐18 (IL‐18) and C‐reactive protein (CRP) were investigated at baseline and 12 months after randomization. Results After 1 year of diet intervention, concentrations of nitrotyrosine (P < 0.01), CRP (P < 0.01), TNF‐α (P < 0.01), IL‐6 (P < 0.01) and IL‐18 (P < 0.01) were increased in the control group compared with the intervention group. In addition, myocardial performance index (P < 0.02) was higher, and transmitral Doppler flow (P < 0.05), pulmonary venous flow analysis (P < 0.02) and ejection fraction (P < 0.05) were lower in the control group, indicating ventricular dys‐synchrony. The concentrations of nitrotyrosine, CRP, TNF‐α and IL‐6 were related to echocardiographic parameters of ventricular dys‐synchrony. Conclusions In subjects with diabetes, red wine consumption, taken with meals, significantly reduces oxidative stress and pro‐inflammatory cytokines as well as improving cardiac function after MI. Moderate red wine intake with meals may have a beneficial effect in the prevention of cardiovascular complications after MI in subjects with diabetes. 相似文献
5.
Peter L. Forster Frank B. Schoenfeld Charles R. Marmar Ariel Janna Lang 《Journal of traumatic stress》1995,8(1):143-149
Irritability is often a problem for patients with Post-Traumatic Stress Disorder (PTSD). We describe two cases that illustrate the use of lithium in the treatment of veterans with PTSD who complained of serious problems with irritability or angry outbursts. These cases are discussed in the context of evidence that lithium may be useful in other patients with disorders of impulse control. The evidence linking disorders of anger and impulse control to a dysregulation in neurotransmitter regulation, particularly in serotonergic pathways, supports a psychopharmacologic approach to treatment. These findings should lead to further study of the role of lithium in the treatment of this symptom complex in patients with PTSD. 相似文献
6.
P. J. Foreman G. Taglialatela L. Angelucci C. P. Turner J. R. Perez-Polo 《Journal of neuroscience research》1993,36(1):10-18
The synthesis of nerve growth factor (NGF) by the hippocampus raises the possibility that NGF may play a role in the regulation of the hypothalamic-pituitary-adrenal axis (HPAA). Subchronic cold stress has been shown to activate the HPAA in a mild noninvasive manner, to stimulate serum glucocorticoid levels, and to perturb NGF binding in hippocampus and basal forebrain. One or repeated episodes of cold stress increased NGF mRNA levels in the hippocampus and p75NGFR mRNA levels in the basal forebrain. These changes were not due to elevated serum glucocorticoid levels since treatment with exogenous corticosterone had no effect on NGF and p75NGFR mRNA levels. Adrenalectomy did not prevent the stress induced increases in NGF and p75NGFR mRNA. © 1993 Wiley-Liss, Inc. 相似文献
7.
8.
A survey of 402 normal subjects (203 men, 199 women) was conducted to assist in distinguishing potential differences in norms of hand strength. Norm data had previously been collected from mixed occupational groups, but in the present study it was hypothesised that people involved in heavy manual work on a daily basis might possess greater hand strength than others. The volunteers were adults working in industry and agriculture; they were subdivided into occupational categories. Measurements of grip, key and palmar pinch using the Jamar dynamometer and B and L pinch gauge were collected, using the protocol described by Mathiowetz. Volunteers also rated their individual hand strength job requirements subjectively. Mean values were established with regard to age, sex, dominance, occupational group and subjective rating. Significant differences were found with regard to age and sex but not to dominance; there was no evidence of differences between occupational groups or between subjective rating and individual scoring, i.e. volunteers who perceived their job as requiring a high degree of strength did not achieve higher test measurements than others. A high interrater reliability was demonstrated when comparing these follow-up measurements with the original data. It was concluded that, for clinical and rehabilitative purposes, therapists can interpret assessment of outcome most accurately by comparing patients' results with the existing norm data. 相似文献
9.
Martin Tepel 《Nephrology, dialysis, transplantation》2003,18(8):1439-1442
Reactive oxygen species: general aspects Reactive oxygen species, including superoxide radicals, hydrogenperoxide, nitric oxide, peroxynitrite, hydroxyl radicals andhypochlorous acid are by-products of normal metabolic processesin cells. Reactive oxygen species can be found in several cellsincluding macrophages and vascular smooth muscle cells. At lowconcentrations reactive oxygen species can act as physiologicalmediators of cellular responses whereas higher concentrationsmay cause cell damage [1,2]. The major sources of reactive oxygenspecies are leakages from the electron transport chains of mitochondriaand endoplasmic reticulum. Cellular energy metabolism is basedon the production of ATP through the electron transport reactionin which O2 accepts electrons and H+ and then is eventuallyreduced to water. Only 12% of the electrons are leakedto generate superoxide radicals in reactions mediated by coenzymeQ and ubiquinone and its complexes. During ageing (and probablyin patients 相似文献
10.
A new decontaminated hassles measure for adults, the Survey of Recent Life Experiences, was developed and validated. An initial pool of 92 items was administered to 100 subjects along with the Perceived Stress Scale. Fifty-one items were selected, based on significant correlations with the latter scale. The alpha reliability of the resultant final form of the Survey of Recent Life Experiences and its correlation with perceived stress were both high. In a separate cross-replication sample of 136 adults, the alpha reliability of the Survey and its correlation against the Perceived Stress Scale remained acceptably high. Moreover, separate-sex analyses supported the reliability and validity of the Survey of Recent Life Experiences across gender. Factor analysis of the Survey yielded six interpretable factors. Intercorrelations among subscales based on these factors were generally modest, suggesting that the scale is relatively free from contamination by psychological distress.The work reported was facilitated by a grant from the Social Sciences and Humanities Research Council of Canada's Small Grant Program, administered by the Office of Research Administration, York University. The authors appreciate the cooperation of staff at the Ontario Science Centre, Toronto, and the assistance of Maria Gurevich in verifying the data. 相似文献