全文获取类型
收费全文 | 2082篇 |
免费 | 233篇 |
出版年
2021年 | 22篇 |
2018年 | 19篇 |
2016年 | 27篇 |
2015年 | 56篇 |
2014年 | 46篇 |
2013年 | 69篇 |
2012年 | 87篇 |
2011年 | 82篇 |
2010年 | 66篇 |
2009年 | 65篇 |
2008年 | 54篇 |
2007年 | 69篇 |
2006年 | 59篇 |
2005年 | 59篇 |
2004年 | 57篇 |
2003年 | 77篇 |
2002年 | 66篇 |
2001年 | 64篇 |
2000年 | 60篇 |
1999年 | 45篇 |
1998年 | 18篇 |
1997年 | 24篇 |
1996年 | 22篇 |
1995年 | 22篇 |
1994年 | 21篇 |
1993年 | 27篇 |
1992年 | 46篇 |
1991年 | 50篇 |
1990年 | 60篇 |
1989年 | 61篇 |
1988年 | 60篇 |
1987年 | 41篇 |
1986年 | 45篇 |
1985年 | 41篇 |
1984年 | 37篇 |
1983年 | 29篇 |
1982年 | 37篇 |
1981年 | 34篇 |
1980年 | 25篇 |
1979年 | 46篇 |
1978年 | 32篇 |
1977年 | 42篇 |
1976年 | 35篇 |
1975年 | 41篇 |
1974年 | 18篇 |
1973年 | 25篇 |
1972年 | 28篇 |
1971年 | 16篇 |
1967年 | 15篇 |
1966年 | 18篇 |
排序方式: 共有2315条查询结果,搜索用时 15 毫秒
61.
62.
63.
In a field trial of 1,257 patients receiving methoxyflurane, trichloroethylene, and nitrous-oxide/oxygen for the relief of pain in labour methoxyflurane has been shown to have certain advantages which support its use in midwifery practice. The trial confirms our objective method for screening an inhalational agent as an obstetric analgesic. 相似文献
64.
65.
66.
67.
Beth L. Young David A. S. Rosen Martin Haulena Allyson G. Hindle Andrew W. Trites 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(1):105-116
The ability to use heart rate (fh) to predict oxygen consumption rates (
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} ) in Steller sea lions and other pinnipeds has been investigated in fasting animals. However, it is unknown whether established
fh:
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} relationships hold under more complex physiological situations, such as when animals are feeding or digesting. We assessed
whether fh could accurately predict
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} in trained Steller sea lions while fasting and after being fed. Using linear mixed-effects models, we derived unique equations
to describe the fh:
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} relationship for fasted sea lions resting on land and in water. Feeding did not significantly change the fh:
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} relationship on land. However, Steller sea lions in water displayed a different fh:
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} relationship after consuming a 4-kg meal compared with the fasting condition. Incorporating comparable published fh:
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} data from Steller sea lions showed a distinct effect of feeding after a 6-kg meal. Ultimately, our study illustrated that
both feeding and physical environment are statistically relevant when deriving
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} from telemetered fh, but that only environment affects the practical ability to predict metabolism from fh. Updating current
bioenergetic models with data gathered using these predictive fh:
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} equations will yield more accurate estimates of metabolic rates of free-ranging Steller sea lions under a variety of physiological,
behavioral, and environmental states. 相似文献
68.
There is a need for safe medications that can effectively support recovery by treating symptoms of protracted abstinence that may precipitate relapse in alcoholics, e.g. craving and disturbances in sleep and mood. This proof-of-concept study reports on the effectiveness of gabapentin 1200 mg for attenuating these symptoms in a non-treatment-seeking sample of cue-reactive, alcohol-dependent individuals. Subjects were 33 paid volunteers with current Diagnostic and Statistical Manual of Mental Disorders-IV alcohol dependence and a strength of craving rating 1 SD or greater for alcohol than water cues. Subjects were randomly assigned to gabapentin or placebo for 1 week and then participated in a within-subjects trial where each was exposed to standardized sets of pleasant, neutral and unpleasant visual stimuli followed by alcohol or water cues. Gabapentin was associated with significantly greater reductions than placebo on several measures of subjective craving for alcohol as well as for affectively evoked craving. Gabapentin was also associated with significant improvement on several measures of sleep quality. Side effects were minimal, and gabapentin effects were not found to resemble any major classes of abused drugs. Results suggest that gabapentin may be effective for treating the protracted abstinence phase in alcohol dependence and that a randomized clinical trial would be an appropriate next step. The study also suggests the value of cue-reactivity studies as proof-of-concept screens for potential antirelapse drugs. 相似文献
69.
Han-Kyu Lee Pravir Kumar Qinghao Fu Kenneth M. Rosen Henry W. Querfurth 《Molecular biology of the cell》2009,20(5):1533-1544
Intraneuronal β-amyloid (Aβi) accumulates early in Alzheimer's disease (AD) and inclusion body myositis. Several organelles, receptor molecules, homeostatic processes, and signal transduction components have been identified as sensitive to Aβ. Although prior studies implicate the insulin-PI3K-Akt signaling cascade, a specific step within this or any essential metabolic or survival pathway has not emerged as a molecular target. We tested the effect of Aβ42 on each component of this cascade. In AD brain, the association between PDK and Akt, phospho-Akt levels and its activity were all decreased relative to control. In cell culture, Aβi expression inhibited both insulin-induced Akt phosphorylation and activity. In vitro experiments identified that β-amyloid (Aβ), especially oligomer preparations, specifically interrupted the PDK-dependent activation of Akt. Aβi also blocked the association between PDK and Akt in cell-based and in vitro experiments. Importantly, Aβ did not interrupt Akt or PI3K activities (once stimulated) nor did it affect more proximal signal events. These results offer a novel therapeutic strategy to neutralize Aβ-induced energy failure and neuronal death. 相似文献
70.