全文获取类型
收费全文 | 210篇 |
免费 | 11篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 15篇 |
基础医学 | 73篇 |
口腔科学 | 3篇 |
临床医学 | 20篇 |
内科学 | 35篇 |
皮肤病学 | 2篇 |
神经病学 | 32篇 |
特种医学 | 4篇 |
外科学 | 15篇 |
综合类 | 10篇 |
预防医学 | 4篇 |
药学 | 3篇 |
中国医学 | 1篇 |
肿瘤学 | 6篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 12篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 10篇 |
2012年 | 11篇 |
2011年 | 12篇 |
2010年 | 13篇 |
2009年 | 11篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 6篇 |
2005年 | 11篇 |
2004年 | 10篇 |
2003年 | 12篇 |
2002年 | 13篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有225条查询结果,搜索用时 46 毫秒
91.
Early restitution of electrocorticogram predicts subsequent behavioral recovery from cardiac arrest.
Andreas R Luft Manuel M Buitrago Joseph S Paul José Hagan Ming-chieh Ding Nitish Thakor Daniel F Hanley 《Journal of clinical neurophysiology》2002,19(6):540-546
Previous studies have shown that parameters of EEG restitution reflect the severity of global hypoxic-ischemic brain injury. Here, the hypothesis is tested that patterns of EEG restitution during the first 4 hours predict later behavioral recovery. Time course and correlations between behavior, electrocorticogram (EcoG), and neuronal injury were investigated in a rodent model of asphyctic cardiac arrest. Forty Wistar rats were subjected to 5 minutes of asphyxia and cardiopulmonary resuscitation. Behavior was assessed by repeated scoring of neurodeficits and open field activity until euthanasia at 48 hours. Electrocorticographic bursting occurred at 13.2 +/- 4 minutes after resuscitation. Bursts increased in frequency and duration until the EcoG reverted to a continuous signal. The resuscitation-continuous EcoG interval correlated with the first appearance of spontaneous movements (r = 0.80, P < 0.05). Larger intervals were associated with hyperactivity in the open field at 24 hours (r = 0.61, P < 0.05), indicating a more severe behavioral deficit. Larger intervals were also associated with worse 48-hour neurodeficit scores (P < 0.05). Neuronal damage in the hippocampus correlated with the degree of open field hyperactivity at 14 hours (P < 0.05). These findings demonstrate a close temporal and prognostic relationship between electrical and behavioral recovery after hypoxic-ischemic brain injury. 相似文献
92.
B. J. Allison K. L. Brain Y. Niu A. D. Kane E. A. Herrera A. S. Thakor K. J. Botting C. M. Cross N. Itani K. L. Skeffington C. Beck D. A. Giussani 《The Journal of physiology》2016,594(5):1247-1264
AbstractAlthough the fetal cardiovascular defence to acute hypoxia and the physiology underlying it have been established for decades, how the fetal cardiovascular system responds to chronic hypoxia has been comparatively understudied. We designed and created isobaric hypoxic chambers able to maintain pregnant sheep for prolonged periods of gestation under controlled significant (10% O2) hypoxia, yielding fetal mean PaO2 levels (11.5 ± 0.6 mmHg) similar to those measured in human fetuses of hypoxic pregnancy. We also created a wireless data acquisition system able to record fetal blood flow signals in addition to fetal blood pressure and heart rate from free moving ewes as the hypoxic pregnancy is developing. We determined in vivo longitudinal changes in fetal cardiovascular function including parallel measurement of fetal carotid and femoral blood flow and oxygen and glucose delivery during the last third of gestation. The ratio of oxygen (from 2.7 ± 0.2 to 3.8 ± 0.8; P < 0.05) and of glucose (from 2.3 ± 0.1 to 3.3 ± 0.6; P < 0.05) delivery to the fetal carotid, relative to the fetal femoral circulation, increased during and shortly after the period of chronic hypoxia. In contrast, oxygen and glucose delivery remained unchanged from baseline in normoxic fetuses. Fetal plasma urate concentration increased significantly during chronic hypoxia but not during normoxia (Δ: 4.8 ± 1.6 vs. 0.5 ± 1.4 μmol l−1, P<0.05). The data support the hypotheses tested and show persisting redistribution of substrate delivery away from peripheral and towards essential circulations in the chronically hypoxic fetus, associated with increases in xanthine oxidase‐derived reactive oxygen species.
Abbreviations
- HIF
- hypoxia‐inducible factor
- IUGR
- intrauterine growth restriction
- NO
- nitric oxide
- •O2−
- superoxide anion
- ROS
- reactive oxygen species
- XO
- xanthine oxidase
93.
Geocadin RG Sherman DL Christian Hansen H Kimura T Niedermeyer E Thakor NV Hanley DF 《Resuscitation》2002,55(2):193-200
INTRODUCTION: The return of neurological function during the early period after resuscitation from cardiac arrest (CA) has not been evaluated systematically. We report the temporal analysis of EEG bursting pattern during the very early periods after resuscitation. DESIGN/METHOD: A balanced group of good and poor outcome animals was selected from a population of rats subjected to either 5 or 7 min of asphyxial cardiac arrest (ACA) on the basis of a single criteria: 24 h neurobehavioral function based on the neurodeficit score (NDS). The EEGs of six consecutive good outcome rats (NDS > or = 60) and six consecutive poor outcome rats (NDS < 60) were selected for the study. The EEGs of these animals were given to two EEG examiners who were blinded to the selection process, the experimental conditions and the neurobehavioral recovery. The EEG bursting characteristics, such as rate, peak and duration of bursting were studied. RESULTS: There was significantly higher EEG bursting in the good outcome animals (P < 0.05) and the burst complexes evolved into continuous activity by 90 min. Lower frequency bursting that persisted and failed to evolve into continuous activity was observed in the poor outcome group. CONCLUSION: Increased EEG bursting during first 30-40 min after resuscitation from moderate to severe ACA was observed in rats with good neurological outcome at 24 h. Early EEG bursting patterns may provide additional prognostication after resuscitation from CA. 相似文献
94.
Devang Thakor Igor Spigelman Yasuhiko Tabata Ichiro Nishimura 《Molecular therapy》2007,15(12):2124-2131
Selective modulation of sensory neuron gene expression could have numerous applications for the peripheral nervous system. Here, we report that subcutaneous peripheral injection of plasmid DNA complexed with a non-viral cationized gelatin (CG) vector led to transgene expression in rat lumbar dorsal root ganglia (DRGs). CG/DNA polyplexes appeared to undergo rapid retrograde transport through sciatic and spinal nerves, with reporter gene messenger RNA (mRNA) expression detectable in L4 and L5 DRGs within 60 hours. Maximum transgene expression was observed for polyplexes formed at 7.5:1 CG-to-DNA weight ratio under salt-free conditions, which generated 615 +/- 112 nm nanoparticles with zeta-potential of 9.4 +/- 0.19 mV. Six days after injection of the CG/DNA polypex, reporter gene protein immunofluorescence was observed in 1,164 +/- 176 DRG neurons, representing an estimated transfection rate of 47% of targeted neurons. Reporter gene expression was not detected in heart, lung, or liver tissues, suggesting a lack of systemic uptake. Measurements of tactile sensitivity indicate that CG/DNA injection did not cause behavioral toxicity. The injection platform was further used for plasmid-driven short hairpin RNA-mediated suppression of glyceraldehyde-3-phosphate dehydrogenase. This non-invasive gene delivery system could be used for the mechanistic study and targeted molecular evaluation of peripheral nervous system pathologies such as neuropathic pain. 相似文献
95.
We report the novel use of laser speckle contrast imaging (LSCI) at multiple exposure times (meLSCI) for enhanced in vivo imaging of the microvascular changes that accompany angiogenesis. LSCI is an optical imaging technique that can monitor blood vessels and the flow therein at a high spatial resolution without requiring the administration of an exogenous contrast agent. LSCI images are obtained under red (632 nm) laser illumination at seven exposure times (1-7 ms) and combined using a curve-fitting approach to obtain high-resolution meLSCI images of the rat brain vasculature. To evaluate enhancement in in vivo imaging performance, meLSCI images are statistically compared to individual LSCI images obtained at a single exposure time. We find that meLSCI reduced the observed variability in the LSCI-based blood-flow estimates by 30% and improved the contrast-to-noise ratio in regions with high microvessel density by 41%. The ability to better distinguish microvessels, makes meLSCI uniquely suited to longitudinal imaging of changes in the vascular microenvironment induced by pathological angiogenesis. We demonstrate this utility of meLSCI by sequentially monitoring, over days, the microvascular changes that accompany wound healing in a mouse ear model. 相似文献
96.
A novel quantitative EEG injury measure of global cerebral ischemia. 总被引:14,自引:0,他引:14
R G Geocadin R Ghodadra T Kimura H Lei D L Sherman D F Hanley N V Thakor 《Clinical neurophysiology》2000,111(10):1779-1787
OBJECTIVE: To develop a novel quantitative EEG (qEEG) based analysis method, cepstral distance (CD) and compare it to spectral distance (SD) in detecting EEG changes related to global ischemia in rats. METHODS: Adult Wistar rats were subjected to asphyxic-cardiac arrest for sham, 1, 3, 5 and 7 min (n=5 per group). The EEG signal was processed and fitted into an autoregressive (AR) model. A pre-injury baseline EEG was compared to selected data segments during asphyxia and recovery. The dissimilarities in the EEG segments were measured using CD and SD. A segment measured was considered abnormal when it exceeded 30% of baseline and its duration was used as the index of injury. A comprehensive Neurodeficit Score (NDS) at 24 h was used to assess outcome and was correlated with CD and SD measures. RESULTS: A higher correlation was found with CD and asphyxia time (r=0.81, P<0.001) compared to SD and asphyxia time (r=0.69, P<0.001). Correlation with cardiac arrest time (MAP<10 mmHg) showed that CD was superior (r=0.71, P<0.001) to SD (r=0.52, P=0.002). CD obtained during global ischemia and 90 min into recovery correlated significantly with NDS at 24 h after injury (Spearman coefficient=-0.83, P<0.005), and was more robust than the traditional SD (Spearman coefficient=-0.63, P<0.005). CONCLUSION: The novel qEEG-based injury index from CD was superior to SD in quantifying early cerebral dysfunction after cardiac arrest and in providing neurological prognosis at 24 h after global ischemia in adult rats. Studying early qEEG changes after asphyxic-cardiac arrest may provide new insights into the injury and recovery process, and present opportunities for therapy. 相似文献
97.
98.
大脑局部急性缺血后热休克蛋白70的免疫组织化学研究 总被引:3,自引:0,他引:3
热休克蛋白70(HSP70)是一种极敏感和可靠的脑缺血的标志。在正常脑内几乎检测不到HSP70mRNA或HSP70蛋白,随着脑缺血时程的增长,HSP70蛋白的表达与细胞受缺血损伤的程度相关,但随着缺血程度加重,HSP70基因转录和/或翻译被阻断。一过... 相似文献
99.
The aim of the paper is to determine the speed of the neurological response to cerebral artery occlusion by monitoring transient
changes in somatosensory evoked potentials (SEPs). SEPs, continuously monitored during temporary clipping of the middle cerebral
artery (MCA) in anaesthetised cats, are analysed. The SEP signals are modelled by a quasi-periodic Fourier series, the coefficients
of which are estimated with the aid of two adaptive least squares estimation algorithms. The energy levels at various harmonics
throughout the protocol are obtained directly from the filter weights. Noise covariance is estimated from pre-stimulus recording,
and the adaptation rate of the algorithm is adjusted sweep-by-sweep to accomodate transient changes in the pre-stimulus noise
level. After the occlusion, a significant decrease (p<0·05) in SEP amplitude is observed. The change in latency is not statistically
significant (p≅0·5). The spectral trends show a sudden decline in energy at all harmonics immediately following occlusion,
although when the amplifier bandwidth is changed to 5–1500 Hz (from an initial setting of 30–1500 Hz), the fundamental frequency
component of the SEP signal shows the greatest responsiveness to injury. The average time constant of the decline in amplitude
resulting from MCA occlusion is only 10·6±4·0 s. It is concluded that rapid detection of cerebral artery occlusion and ischaemia
may be feasible by continuously monitoring SEP signals and analysing transient changes in time and frequency domains. 相似文献
100.
Effect of cigarette smoke on endothelial regeneration in vivo and nitric oxide levels 总被引:5,自引:0,他引:5
Sarkar R Gelabert HA Mohiuddin KR Thakor DK Santibanez-Gallerani AS 《The Journal of surgical research》1999,82(1):43-47
BACKGROUND: Cigarette smoking accelerates atherosclerosis and restenosis after vascular reconstruction. The mechanisms by which smoking alters vessel structure after injury are unclear. This study examined the effects of cigarette smoking on endothelial regeneration, an important component of arterial remodeling. MATERIALS AND METHODS: Adult male rats were subjected to balloon injury of the thoracic aorta and exposed to mainstream cigarette smoke via a Griffith-type smoking machine for 2 weeks. Control groups included rats which were restrained in the machine but not smoked and a group not utilizing the machine. Aortic reendothelialization was determined using Evan's blue staining of the arterial surface. Serum levels of nitric oxide were measured to determine if smoke exposure altered this potential endothelial cell mitogen. RESULTS: Cigarette smoking increased aortic endothelial regeneration (78.4 +/- 4.6% vs 59.2 +/- 2.1%, P < 0.05) and was associated with an increase in serum nitric oxide level (59.9 +/- 7. 1 microM vs 28.5 +/- 1.8 microM, P < 0.05). Daily restraint alone in the smoking machine had no effect on endothelial regeneration. CONCLUSIONS: This is the first report on the effects of smoking on endothelial regeneration and demonstrates that smoking increases reendothelialization after large vessel injury and serum levels of nitric oxide, an EC mitogen. 相似文献