全文获取类型
收费全文 | 1503篇 |
免费 | 143篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 16篇 |
妇产科学 | 45篇 |
基础医学 | 239篇 |
口腔科学 | 20篇 |
临床医学 | 133篇 |
内科学 | 427篇 |
皮肤病学 | 17篇 |
神经病学 | 153篇 |
特种医学 | 26篇 |
外科学 | 129篇 |
综合类 | 33篇 |
预防医学 | 97篇 |
眼科学 | 82篇 |
药学 | 79篇 |
肿瘤学 | 149篇 |
出版年
2023年 | 10篇 |
2022年 | 13篇 |
2021年 | 37篇 |
2020年 | 25篇 |
2019年 | 28篇 |
2018年 | 31篇 |
2017年 | 26篇 |
2016年 | 38篇 |
2015年 | 29篇 |
2014年 | 44篇 |
2013年 | 49篇 |
2012年 | 81篇 |
2011年 | 87篇 |
2010年 | 51篇 |
2009年 | 41篇 |
2008年 | 75篇 |
2007年 | 71篇 |
2006年 | 92篇 |
2005年 | 84篇 |
2004年 | 68篇 |
2003年 | 86篇 |
2002年 | 72篇 |
2001年 | 62篇 |
2000年 | 56篇 |
1999年 | 47篇 |
1998年 | 16篇 |
1997年 | 21篇 |
1996年 | 13篇 |
1995年 | 21篇 |
1994年 | 17篇 |
1993年 | 19篇 |
1992年 | 28篇 |
1991年 | 20篇 |
1990年 | 15篇 |
1989年 | 19篇 |
1988年 | 15篇 |
1987年 | 11篇 |
1986年 | 13篇 |
1985年 | 10篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1981年 | 6篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1975年 | 12篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1969年 | 5篇 |
1968年 | 7篇 |
排序方式: 共有1652条查询结果,搜索用时 31 毫秒
1.
2.
Veena Kumari Jeffrey A. Gray Philip J. Corr Owen F. Mulligan Paul A. Cotter Stuart A. Checkley 《Psychopharmacology》1997,129(3):271-276
The effects of an indirect dopamine-agonist, d-amphetamine, and a non-selective dopamine receptor antagonist, haloperidol, were investigated in normal male volunteers using
a between-subjects double-blind design in a procedural learning task, thought mainly to involve unconscious/automatic learning.
The results showed: (1) d-amphetamine facilitated response speed, whereas haloperidol inhibited it, in comparison to placebo; (2) the linear increase
in procedural learning corresponded with pharmacological manipulation of degree of dopaminergic activity, i.e. subjects given
haloperidol showed the least, and subjects given d-amphetamine the greatest, procedural learning. The implications of these findings are discussed in relation to investigation
of abnormalities of procedural learning processes in schizophrenia.
Received: 28 June 1996/Final version: 2 October 1996 相似文献
3.
Chronic vitamin E treatment prevents defective endothelium-dependent relaxation in diabetic rat aorta 总被引:2,自引:2,他引:0
Summary We examined the effect in rats of 2 months of streptozotocin-induced diabetes mellitus on relaxation and contraction of aortas in vitro. A further diabetic group was treated from time of diabetes induction with a 1% dietary supplement of vitamin E. Diabetes caused a 26.5% deficit (p<0.001) in maximum endothelium-dependent relaxation to acetylcholine in phenylephrine-precontracted aortas. This was 64.3% attenuated (p<0.01) by vitamin E treatment; maximum relaxation was not significantly altered compared to non-diabetic rats. Vitamin E treatment of non-diabetic rats did not significantly affect acetylcholine-induced relaxation. Diabetes or treatment did not significantly alter acetylcholine sensitivity. Endothelium-independent relaxation response to glyceryl trinitrate was not affected by diabetes or vitamin E treatment, indicating that vascular smooth muscle responses to nitric oxide remained unaltered. There was a 35.4% reduction in the maximum contractile response to phenylephrine with diabetes (p<0.05) which was unaffected by vitamin E treatment. The data suggest that the chronic deficit in nitric oxide-mediated endothelium-dependent relaxation in diabetes depends largely upon excess activity of reactive oxygen species. Treatment with vitamin E to increase free radical scavenging specifically protected vascular endothelium although it had no effect on deficits in vascular smooth muscle contractile responses.Abbreviations NO
Nitric oxide
- ARI
aldose reductase inhibitor
- ACH
acetylcholine
- GTN
glyceryl trinitrate
- GSH
reduced form of glutathione
- EC50
effective concentration for 50% of the maximal response 相似文献
4.
R Cotter R Johnson M Tumbelson J Dexter S Young C A Taylor F Cosmas W B Rowe L Lin 《JPEN. Journal of parenteral and enteral nutrition》1988,12(2):121-126
The ability of soybean oil lipid emulsions to affect essential fatty acid deficiency (EFAD) and plasma fatty acid distribution was studied in neonatal pigs. The test animals were maintained on a fat-free diet prior to administration of lipid emulsion. Plasma and red blood cell (RBC) membrane levels of essential [linoleic (C-18:2 omega 6) and arachidonic (C-20:4 omega 6)] and nonessential [palmitic (C-16, palmitoleic (C-16:1 omega 7), stearic (C-18), and oleic (C-18:1 omega 9)] fatty acids and the triene:tetraene ratio [5,8,11-eicosatrienoic acid (C-20:3 omega 9):arachidonic acid (C-20:4 omega 6)] were monitored to ascertain the establishment of EFAD and its correction. Nonessential fatty acids were studied, as these components of lipid therapy have received little attention. Results indicate that soybean oil emulsions are effective in reversing fatty acid profiles found in EFAD, and both essential and nonessential fatty acids are under strict metabolic control. 相似文献
5.
Introduction: apoptosis in the immune system. 总被引:5,自引:0,他引:5
6.
7.
8.
Functional changes in slow-twitch soleus and fast-twitch extensor digitorum longus muscles were assessed after 2 mo of streptozocin-induced diabetes in rats. For soleus, there was a slowing of twitch times both for contraction and relaxation and a reduction of maximum tetanic relaxation rate. There was little effect on strength performance assessed by maximal tetanic tension production. Treatment with the aldose reductase inhibitor ponalrestat largely prevented relaxation defects but had little effect on contraction. For the fast muscle, twitch times were relatively unaffected, but maximum tetanic relaxation rate was reduced. In addition, tetanic tension output decreased. These changes were largely prevented by ponalrestat treatment. The effects of partial insulin therapy were also investigated. This regimen reduced hypoinsulinemia, but sufficient hyperglycemia remained to stimulate the polyol pathway. It prevented the slowing of soleus twitch contraction but had no effect on relaxation. For extensor digitorum longus, insulin produced further deleterious effects on tetanic tension and maximum relaxation rate, which were antagonized by ponalrestat. A 1% dietary myo-inositol supplement had little effect on contractile function in slow or fast muscles. It was concluded that polyol-pathway activity is an important factor underlying skeletal muscle functional changes in diabetes, probably acting through disruption of Ca2+ handling. Hypoinsulinemia was considered a secondary factor causing atrophy, particularly of fast muscles. There was no evidence of effects dependent on neuropathy. 相似文献
9.
10.