全文获取类型
收费全文 | 1263796篇 |
免费 | 94815篇 |
国内免费 | 1578篇 |
专业分类
耳鼻咽喉 | 16313篇 |
儿科学 | 40999篇 |
妇产科学 | 34947篇 |
基础医学 | 189387篇 |
口腔科学 | 34731篇 |
临床医学 | 117750篇 |
内科学 | 247789篇 |
皮肤病学 | 27278篇 |
神经病学 | 101847篇 |
特种医学 | 46758篇 |
外国民族医学 | 265篇 |
外科学 | 178576篇 |
综合类 | 25749篇 |
现状与发展 | 3篇 |
一般理论 | 568篇 |
预防医学 | 104649篇 |
眼科学 | 28044篇 |
药学 | 92556篇 |
7篇 | |
中国医学 | 2022篇 |
肿瘤学 | 69951篇 |
出版年
2018年 | 13530篇 |
2017年 | 10390篇 |
2016年 | 11323篇 |
2015年 | 13078篇 |
2014年 | 17999篇 |
2013年 | 27477篇 |
2012年 | 37572篇 |
2011年 | 39966篇 |
2010年 | 23053篇 |
2009年 | 22250篇 |
2008年 | 37752篇 |
2007年 | 40381篇 |
2006年 | 39962篇 |
2005年 | 39095篇 |
2004年 | 37542篇 |
2003年 | 35953篇 |
2002年 | 34864篇 |
2001年 | 56029篇 |
2000年 | 57042篇 |
1999年 | 48095篇 |
1998年 | 13396篇 |
1997年 | 12222篇 |
1996年 | 12643篇 |
1995年 | 11914篇 |
1994年 | 11107篇 |
1993年 | 10399篇 |
1992年 | 38198篇 |
1991年 | 37671篇 |
1990年 | 36445篇 |
1989年 | 35258篇 |
1988年 | 32690篇 |
1987年 | 32027篇 |
1986年 | 30524篇 |
1985年 | 28786篇 |
1984年 | 21941篇 |
1983年 | 19192篇 |
1982年 | 11364篇 |
1981年 | 10321篇 |
1979年 | 20944篇 |
1978年 | 15393篇 |
1977年 | 12790篇 |
1976年 | 11845篇 |
1975年 | 12810篇 |
1974年 | 15588篇 |
1973年 | 15362篇 |
1972年 | 14512篇 |
1971年 | 13552篇 |
1970年 | 12786篇 |
1969年 | 12065篇 |
1968年 | 11229篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
As many as 136 patients (76 with Bechterew's disease, 40 with Reiter's disease and 20 with psoriatic arthritic) and 35 practically healthy persons were examined by echocardiography combined with electro-, phonocardiographic and by clinical, x-ray and laboratory methods. 62 patients were examined over time (within a period from 1 to 4 years). Echocardiography was used to study in detail the central and intracardiac hemodynamics, the status of the valvular apparatus of the heart and of the aorta. The different clinical characteristics of the disease were established to make a concrete contribution to the development of cardial pathology. The disease duration is the most significant characteristics. A long-term prospective follow-up coupled with echocardiographic examinations made over time enabled one to specify the structure of heart damage in patients suffering from Bechterew's disease, Reiter's disease and psoriatic arthritis depending on the hypothetic nature of the damage. 相似文献
994.
A Sultan C Piot D Mariano-Goulart J P Daures F Comte E Renard A Avignon 《Diabetic medicine》2006,23(4):410-418
AIMS: To assess the association between abnormal stress myocardial perfusion imaging (MPI) and cardiac events (CE) in asymptomatic patients with diabetes and with > or = 1 additional risk factor. Predictors of abnormal stress MPI were also evaluated. METHODS: Four hundred and forty-seven consecutive patients who underwent stress MPI were prospectively followed for 2.1 [0.5-4.1] years for the subsequent occurrence of hard CE (myocardial infarction and sudden or coronary death) and soft CE (unstable angina and ischaemic heart failure requiring hospitalization). Re-vascularization procedures performed as a result of the screening protocol were not included in the analysis. RESULTS: Follow-up was successful in 419 of 447 patients (94%), of whom 71 had abnormal MPI at baseline. Medical therapy was intensified in all subjects and especially in those with abnormal MPI. Twenty-three patients with abnormal MPI underwent a re-vascularization procedure. CEs occurred in 14 patients, including six of 71 patients (8.5%) with abnormal MPI and eight of 348 patients (2.3%) with normal MPI (P < 0.005). Only two patients developed a hard CE and 12 a soft CE. In multivariate analysis, abnormal MPI was the strongest predictor for CEs [odds ratio (OR) (95% CI) = 5.6 (1.7-18.5)]. Low-density lipoprotein cholesterol > or = 3.35 mmol/l [OR (95% CI) = 7.3; 1.5-34.7] and age > median [OR (95% CI) = 6.0 (1.2-28.6)] were additional independent predictors for CE. The independent predictors for abnormal MPI were male gender, plasma triglycerides > or = 1.70 mmol/l, creatinine clearance < 60 ml/min and HbA1c > 8%, with male gender the strongest [OR (95% CI) = 4.0 (1.8-8.8)]. CONCLUSIONS: Asymptomatic patients with diabetes in this study had a very low hard cardiac event rate over an intermediate period. This could be explained by the effects of intervention or by the low event rate in the background population. Randomized studies of cardiac heart disease screening are required in asymptomatic subjects with diabetes to determine the effectiveness of this intervention. 相似文献
995.
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
996.
The calculation of the extent of the ring scotoma around positive lenses, as conventionally taught to students of clinical optics, indicates that the scotoma is of a significant size. Using knife-edge lenses this study shows that the calculations are invalid due to the finite size of the eye's entrance pupil and in many instances the scotoma is shown not to exist. The effect noticed in clinical practice is probably largely due to the frame and the edging techniques used which add to the refractive scotoma which is present with high powered lenses, large apertures and/or small pupil sizes. 相似文献
997.
998.
999.
Dr. E. Mietzsch M. Koch M. Schaldach J. Werner B. Bellenberg K. U. Wentz 《Medical & biological engineering & computing》1998,36(6):673-678
The application of spin-echo magnetic resonance imaging sequences on non-invasive temperature imaging for temperature mapping
of human limbs is investigated. In an in vitro expriment performed on a meat sample, the equilibrium magnetisation P and the
spin-lattice relaxation time T1 are calculated from the values for the repetition time TR and the signal intensities obtained by a spin-echo sequence at
different tissue temperatures tures as measured by a fibre-optic probe. T1 is linearly correlated to the tissue temperature, and P is linearly correlated to the reciprocal value of the absolute temperature.
Both effects, taken together, lead to a non-linear dependency of the signal intensity on temperature. Therefore a TR leading
to maximum temperature dependency of the signal intensity is calculated and used in the futher experiments. In the in vivo
experiments, the lower legs of two volunteers are cooled from outside. Images are acquired with a spin-echo sequence (1.5T,
TR=1200 ms, TE=10 ms). A rise in signal intensity in the muscle with falling skin temperature is observed, particularly in
more peripheral muscle layers. This study shows that spin-echo sequences can be used to monitor temperature changes and temperature
differences in living muscle tissue. 相似文献
1000.