全文获取类型
收费全文 | 999篇 |
免费 | 46篇 |
国内免费 | 14篇 |
专业分类
儿科学 | 45篇 |
妇产科学 | 6篇 |
基础医学 | 120篇 |
口腔科学 | 17篇 |
临床医学 | 122篇 |
内科学 | 255篇 |
皮肤病学 | 14篇 |
神经病学 | 66篇 |
特种医学 | 200篇 |
外科学 | 49篇 |
综合类 | 37篇 |
一般理论 | 1篇 |
预防医学 | 51篇 |
眼科学 | 2篇 |
药学 | 53篇 |
肿瘤学 | 21篇 |
出版年
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 13篇 |
2014年 | 28篇 |
2013年 | 32篇 |
2012年 | 43篇 |
2011年 | 32篇 |
2010年 | 22篇 |
2009年 | 35篇 |
2008年 | 25篇 |
2007年 | 39篇 |
2006年 | 33篇 |
2005年 | 44篇 |
2004年 | 20篇 |
2003年 | 31篇 |
2002年 | 27篇 |
2001年 | 30篇 |
2000年 | 29篇 |
1999年 | 35篇 |
1998年 | 42篇 |
1997年 | 49篇 |
1996年 | 39篇 |
1995年 | 43篇 |
1994年 | 24篇 |
1993年 | 26篇 |
1992年 | 19篇 |
1991年 | 21篇 |
1990年 | 19篇 |
1989年 | 14篇 |
1988年 | 24篇 |
1987年 | 24篇 |
1986年 | 20篇 |
1985年 | 19篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 18篇 |
1981年 | 12篇 |
1980年 | 22篇 |
1979年 | 4篇 |
1978年 | 12篇 |
1977年 | 22篇 |
1976年 | 12篇 |
1975年 | 8篇 |
1963年 | 3篇 |
1962年 | 1篇 |
1943年 | 1篇 |
排序方式: 共有1059条查询结果,搜索用时 15 毫秒
991.
Association between high-density lipoprotein and cognitive impairment in the oldest old 总被引:8,自引:0,他引:8
van Exel E de Craen AJ Gussekloo J Houx P Bootsma-van der Wiel A Macfarlane PW Blauw GJ Westendorp RG 《Annals of neurology》2002,51(6):716-721
Low high-density lipoprotein cholesterol is associated with an increased risk for cardiovascular disease and stroke. At the same time, cardiovascular disease and stroke are important risk factors for dementia. We assessed the association between total and fractionated cholesterol and cognitive impairment and explored whether observed associations were dependent on or independent of atherosclerotic disease. In a population-based study, total cholesterol, triglycerides, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were measured in 561 subjects 85 years old and grouped in three equal strata representing decreasing serum concentrations. History of cardiovascular disease and stroke was determined. All subjects completed the Mini-Mental State Examination (MMSE), and the presence of dementia was determined. Median MMSE scores were significantly lower in subjects with low high-density lipoprotein cholesterol (25 points vs 27 points, p < 0.001). No differences in MMSE scores were found for other lipids and lipoproteins. MMSE scores in subjects with and without cardiovascular disease were 26 and 27 points (p = 0.007), respectively, and in subjects with and without stroke were 21 and 26 points (p < 0.001), respectively. The associations between low MMSE scores and low high-density lipoprotein cholesterol remained significant after subjects with cardiovascular disease or stroke were excluded. In a comparison of subjects with low high-density lipoprotein cholesterol with subjects with high high-density lipoprotein cholesterol, the odds ratio for dementia was 2.3 (95% confidence interval, 1.2-4.3), and in subjects without cardiovascular disease or stroke, it was 3.7 (95% confidence interval, 1.3-10.1). All odds ratios were unaffected by education, low-density lipoprotein cholesterol, triglycerides, and survival. Low high-density lipoprotein cholesterol is associated with cognitive impairment and dementia. At least part of the association between high-density lipoprotein cholesterol and cognitive function is independent of atherosclerotic disease. 相似文献
992.
Previous studies suggest that the short-term outcome in severely depressed elderly in The Netherlands is worse compared to other studies in the Western world. The present study examines the long-term prognosis of hospitalized elderly patients with major depressive disorder and possible predictors of outcome. One hundred and five elderly inpatients with unipolar major depression, admitted by regional mental health services in a geographically delimited area, were evaluated six to eight years after index episode by trained residents using a structured diagnostic interview (C.I.D.I.) The GP was interviewed using a standard questionnaire. At follow-up 40% of the original sample had died. Of the survivors 33% had fared well, 24% had a relapsing course, 22% had residual symptoms, 11% were continuously ill, and 9% had probable dementia. With respect to prognostic factors, personality disorder predicted a worse outcome. All patients with a major depressive disorder at follow-up received specialised care and used antidepressants. None of the patients received ECT. The mortality rate in clinically treated elderly with major depressive disorder is high. Among survivors the long-term prognosis in The Netherlands is comparable with other studies to date. The presence of a personality disorder predicts worse outcome. Though the accessibility of services seems to be good, more vigorous treatment was not applied. 相似文献
993.
994.
Seven day administration of lamotrigine in epilepsy: placebo-controlled add-on trial 总被引:2,自引:0,他引:2
C D Binnie D J Beintema R M Debets W Van Emde Boas J W Meijer H Meinardi A W Peck A M Westendorp W C Yuen 《Epilepsy research》1987,1(3):202-208
A double-blind placebo-controlled trial of 7 days administration of lamotrigine as add-on therapy was performed in 10 patients with frequent therapy-resistant, chiefly partial, seizures. Dosage was adjusted on the basis of estimated half-life. Six patients showed a 50% seizure reduction on lamotrigine and two an increase. Side effects (ataxia, dizziness and apathy) occurred in 3 patients, but only at blood levels above 3 micrograms/ml, and were rapidly relieved when the dose was reduced in two. EEG spike counts were significantly reduced on lamotrigine. There was no evidence of interactions with co-medication. 相似文献
995.
996.
997.
998.
R G Westendorp A N Roos M Fr?lich A E Meinders 《The Netherlands journal of medicine》1991,38(5-6):249-253
The effect of positive-pressure ventilation on plasma atrial natriuretic peptide (ANP) concentrations was investigated in sixteen patients weaning from the ventilator. During spontaneous ventilation plasma ANP concentrations rose significantly from 59 (16-270) to 67 (13-320) pg/ml (median and range, P less than 0.05) and mean arterial blood pressure rose from 84 +/- 3 to 92 +/- 3 mmHg (mean +/- SEM, P less than 0.05) if compared with periods of positive-pressure ventilation. This increase in plasma ANP concentrations occurred irrespective of the underlying disease and the wide scatter of the ANP plasma levels found in individual patients. As right atrial stretch is the major stimulus for the release of the ANP the data indicate a decrease in cardiac output during positive-pressure ventilation following an impaired central venous return to the heart. 相似文献
999.
1000.
Alzheimer disease: quantitative analysis of I-123-iodoamphetamine SPECT brain imaging 总被引:3,自引:0,他引:3
Hellman RS; Tikofsky RS; Collier BD; Hoffmann RG; Palmer DW; Glatt SL; Antuono PG; Isitman AT; Papke RA 《Radiology》1989,172(1):183-188
To enable a more quantitative diagnosis of senile dementia of the Alzheimer type (SDAT), the authors developed and tested a semiautomated method to define regions of interest (ROIs) to be used in quantitating results from single photon emission computed tomography (SPECT) of regional cerebral blood flow performed with N-isopropyl iodine-123-iodoamphetamine. SPECT/IMP imaging was performed in ten patients with probable SDAT and seven healthy subjects. Multiple ROIs were manually and semiautomatically generated, and uptake was quantitated for each ROI. Mean cortical activity was estimated as the average of the mean activity in 24 semiautomatically generated ROIs; mean cerebellar activity was determined from the mean activity in separate ROIs. A ratio of parietal to cerebellar activity less than 0.60 and a ratio of parietal to mean cortical activity less than 0.90 allowed correct categorization of nine of ten and eight of ten patients, respectively, with SDAT and all control subjects. The degree of diminished mental status observed in patients with SDAT correlated with both global and regional changes in IMP uptake. 相似文献