全文获取类型
收费全文 | 670篇 |
免费 | 44篇 |
国内免费 | 15篇 |
专业分类
儿科学 | 44篇 |
妇产科学 | 4篇 |
基础医学 | 68篇 |
口腔科学 | 21篇 |
临床医学 | 112篇 |
内科学 | 112篇 |
皮肤病学 | 9篇 |
神经病学 | 16篇 |
特种医学 | 195篇 |
外科学 | 36篇 |
综合类 | 35篇 |
预防医学 | 9篇 |
眼科学 | 5篇 |
药学 | 44篇 |
肿瘤学 | 19篇 |
出版年
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 15篇 |
2013年 | 12篇 |
2012年 | 4篇 |
2011年 | 10篇 |
2010年 | 14篇 |
2009年 | 19篇 |
2008年 | 10篇 |
2007年 | 20篇 |
2006年 | 12篇 |
2005年 | 12篇 |
2004年 | 6篇 |
2003年 | 11篇 |
2002年 | 5篇 |
2001年 | 10篇 |
2000年 | 5篇 |
1999年 | 21篇 |
1998年 | 40篇 |
1997年 | 48篇 |
1996年 | 38篇 |
1995年 | 40篇 |
1994年 | 24篇 |
1993年 | 27篇 |
1992年 | 14篇 |
1991年 | 19篇 |
1990年 | 16篇 |
1989年 | 13篇 |
1988年 | 23篇 |
1987年 | 26篇 |
1986年 | 20篇 |
1985年 | 21篇 |
1984年 | 9篇 |
1983年 | 10篇 |
1982年 | 18篇 |
1981年 | 15篇 |
1980年 | 23篇 |
1979年 | 5篇 |
1978年 | 14篇 |
1977年 | 24篇 |
1976年 | 12篇 |
1975年 | 9篇 |
1963年 | 2篇 |
1957年 | 1篇 |
1943年 | 1篇 |
1933年 | 1篇 |
排序方式: 共有729条查询结果,搜索用时 31 毫秒
81.
Robertson RT; Gallardo KA; Claytor KJ; Ha DH; Ku KH; Yu BP; Lauterborn JC; Wiley RG; Yu J; Gall CM; Leslie FM 《Cerebral cortex (New York, N.Y. : 1991)》1998,8(2):142-155
The role of basal forebrain-derived cholinergic afferents in the
development of neocortex was studied in postnatal rats. Newborn rat pups
received intraventricular injections of 192 IgG-saporin. Following survival
periods ranging from 2 days to 6 months, the brains were processed to
document the cholinergic lesion and to examine morphological consequences.
Immunocytochemistry for choline acetyltransferase (ChAT) and in situ
hybridization for ChAT mRNA demonstrate a loss of approximately 75% of the
cholinergic neurons in the medial septum and nucleus of the diagonal band
of Broca in the basal forebrain. In situ hybridization for glutamic acid
decarboxylase mRNA reveals no loss of basal forebrain GABAergic neurons.
Acetylcholinesterase histochemistry demonstrates a marked reduction of the
cholinergic axons in neocortex. Cholinergic axons are reduced throughout
the cortical layers; this reduction is more marked in medial than in
lateral cortical areas. The thickness of neocortex is reduced by
approximately 10%. Retrograde labeling of layer V cortico-collicular
pyramidal cells reveals a reduction in cell body size and also a reduction
in numbers of branches of apical dendrites. Spine densities on apical
dendrites are reduced by approximately 20-25% in 192 IgG- saporin-treated
cases; no change was detected in number of spines on basal dendrites. These
results indicate a developmental or maintenance role for cholinergic
afferents to cerebral cortical neurons.
相似文献
82.
83.
84.
Diabetic retinopathy remains a major cause of loss of vision. The Diabetes Control and Complications Trial (DCCT) has implicated hyperglycaemia as a probable major direct causative factor in the pathogenesis of diabetic retinopathy. There are several plausible mechanisms by which high glucose concentrations could lead to the functional and later structural changes characterising diabetic retinopathy. These include increased activity of the aldose reductase pathway, increase de novo synthesis of diacylglycerol from glucose, causing protein kinase C activation, increased non-enzymatic glycation and increased oxidative damage. The demonstration of the potential roles of these pathways and the subsequent effects of growth factors in enhancing angiogenesis provide potential new approaches to the prevention and treatment of diabetic retinopathy. 相似文献
85.
The authors describe a magnetic resonance imaging method for examination of the glenoid labrum of the shoulder joint that utilizes a radial fast-imaging sequence. Seven shoulders were examined: a total of five in three healthy asymptomatic volunteers, one in a symptomatic patient not suspected of having a lesion of the glenoid labrum, and one in a patient with recurrent shoulder dislocation and surgical proof of an extensive tear of the labrum. The preliminary results suggest that this technique may advantageously demonstrate pathologic changes in the glenoid labrum and may contribute to the evaluation of the unstable and painful shoulder. 相似文献
86.
Tetrahydrocannabinol vs. prochlorperazine. The effects of two antiemetics on patients undergoing radiotherapy 总被引:1,自引:0,他引:1
The authors tested the effectiveness of orally administered delta-9-tetrahydrocannabinol (THC) as compared to prochlorperazine for the alleviation of symptoms, such as vomiting and nausea, experienced by patients receiving radiotherapy. The test subjects rated the severity of their illness, as well as the extent of their subsequent moods, their level of concentration, their amount of physical activity, and their desire for social interaction. They chose the drug they preferred and recorded its side effects. The use of THC was slightly more beneficial than the use of prochlorperazine. 相似文献
87.
88.
Computed tomography of the thorax 总被引:2,自引:0,他引:2
Computed tomography (CT) provides a valuable new perspective in assessing abnormalities of the thorax. In the patient with a mediastinal mass or widening detected by plain chest radiography, a definitive diagnosis is sometimes possible which would not be obtainable by conventional noninvasive radiological techniques. In certain clinical situations, CT is a highly sensitive modality for examining the lungs. The proved and potential clinical uses of CT in solving diagnostic problems of the thorax are discussed. 相似文献
89.
The authors describe the use of a desk-top computer to analyze processor status. Quality control data (sensitometry, densitometry, thermometry, etc.) are collected conventionally. Analysis of the data is subsequently performed using specially designed software. This computer analysis results in a small savings in time and in greatly improved management and presentation of quality control data. 相似文献
90.