首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   110篇
  免费   5篇
  国内免费   3篇
  2020年   1篇
  2019年   4篇
  2018年   3篇
  2017年   3篇
  2016年   8篇
  2015年   3篇
  2014年   7篇
  2013年   24篇
  2011年   3篇
  2010年   4篇
  2009年   7篇
  2008年   5篇
  2007年   3篇
  2006年   5篇
  2005年   7篇
  2004年   3篇
  2003年   5篇
  2002年   6篇
  2001年   4篇
  2000年   6篇
  1999年   1篇
  1998年   2篇
  1997年   1篇
  1994年   1篇
  1993年   1篇
  1990年   1篇
排序方式: 共有118条查询结果,搜索用时 15 毫秒
31.
This study examined if subcortical stroke was associated with impaired facial emotion recognition. Furthermore, the lateralization of the impairment and the differential profiles of facial emotion recognition deficits with localized thalamic or basal ganglia damage were also studied. Thirty-eight patients with subcortical strokes and 19 matched normal controls volunteered to participate. The participants were individually presented with morphed photographs of facial emotion expressions over multiple trials. They were requested to classify each of these morphed photographs according to Ekman's six basic emotion categories. The findings indicated that the clinical participants had impaired facial emotion recognition, though no clear lateralization pattern of impairment was observed. The patients with localized thalamic damage performed significantly worse in recognizing sadness than the controls. Longitudinal studies on patients with subcortical brain damage should be conducted to examine how cognitive reorganization post-stroke would affect emotion recognition.  相似文献   
32.
Using an auditory semantic priming paradigm, the present study investigated the abilities of left-hemisphere-damaged (LHD) non-fluent aphasic, right-hemisphere-damaged (RHD) and normal control individuals to access, out of context, the multiple meanings of three types of ambiguous words, namely homonyms (e.g., "punch"), metonymies (e.g., "rabbit"), and metaphors (e.g., "star"). In addition, the study tested certain predictions of the "suppression deficit" and "coarse semantic coding" hypotheses that have been proposed to account for the linguistic deficits typically observed after RH damage. Homonymous, metonymous, and metaphorical words were used as primes followed after a short (100 ms) or a long (1000 ms) inter-stimulus interval (ISI) by dominant-meaning-related, subordinate-meaning-related or unrelated target words. No significant group effects were found, and for both ISIs, dominant- and subordinate-related targets were facilitated relative to unrelated control targets for the homonymy and metonymy conditions. In contrast, for the metaphor condition, only targets related to the dominant meaning were facilitated. These findings provide only partial support for the "suppression deficit" hypothesis and no support for the "coarse semantic coding" hypothesis (as interpreted herein) indicating that patients with focal LH or RH damage can access the multiple meanings of ambiguous words and exhibit processing abilities comparable to those of older normal control subjects, at least at the single-word level.  相似文献   
33.
This study explores the relation of white matter disorder (WMD) to intralimb coordination patterns in premature infants with very low birth weight (VLBW). We specifically measured the temporal-spatial characteristics of intralimb coordination patterns of the legs. Three groups of infants were compared at one month corrected age (CA): 10 premature infants born VLBW and WMD (PTWMD), 10 premature infants born VLBW without WMD (PT) and 10 full term infants (FT). Using kinematic variables, we discriminate among VLBW infants with WMD from the two comparison groups. Infants born with WMD maintain patterns of tight coupling among leg joints (all flexion or all extension) while PT and FT term infants have begun to decouple leg joints by this age (combinations of flexion with extension). The coupling pattern is captured through joint correlations, discrete relative phase, and phase plane portraits. The PTWMD infants also demonstrate aberrant patterns of coordination evident through both temporal and spatial characteristics of the kicks. This is the first evidence that movement disorder associated with brain lesions can be identified and quantified with kinematic variables as early as one month of age.  相似文献   
34.
We examined the oxidative damage and antioxidant defense changes with immobilization-induced emotional stress in the rat brain. Though superoxide dismutase activity remained unchanged, brain peroxidation was significantly accelerated by the immobilization stress. Membrane fluidity study with spin labeling in brain cortical membrane showed that immobilization stress induced an increase in microviscosity of membrane layer near the surface and in the ordering of membrane proteins but a decrease in microviscosity at the core of the membrane bilayer. The Na, K-ATPase activity decreased whereas the levels of some monoamines and their metabolites increased along with their metabolic rate. The administration of reduced glutathione showed a protective effect on the immobilization stress-induced stomach bleeding, oxidative damage and abnormal changes in the brain antioxidant defenses. Based on these results and on previous reports, we hypothesize that immobilization stress may induce the formation of reactive oxygen species which weakens the brain antioxidant defenses and induces oxidative damage. The antioxidant administration of reduced glutathione provides further evidence to support the above hypothesis, and also may provide clues in the search for a rational therapy to emotional stress. A possible correlation of emotional stress to aging is also discussed.  相似文献   
35.
Measures of electrical brain activity (event-related potentials, ERPs) have been useful in understanding language processing for several decades. Extant data suggest that the amplitude of the N400 component of the ERP is a general index of the ease or difficulty of retrieving stored conceptual knowledge associated with a word, which is dependent on both the stored representation itself, and the retrieval cues provided by the preceding context. Recordings from patients with brain damage, intracranial recordings, and magnetoencephalographic data implicate a (probably large portion of) the left temporal lobe as the largest source of the N400 semantic context effect, with a substantial but lesser contribution from the right temporal lobe. Event-related functional magnetic resonance (fMRI) studies using semantic context manipulations are dominated by observations of greater hemodynamic activity for incongruent sentence completions or semantically unrelated words than congruent or related words, consistent with the direction of the ERP effect. The locations of the hemodynamic effects show some variability across studies, but one commonly identified region is the left superior temporal gyrus, which is compatible with the electrophysiological results. A second commonly identified region in the fMRI studies is the left inferior frontal gyrus, which does not appear to make a substantial contribution to the N400 effect.  相似文献   
36.
应用24h动态血压监测(ABPM)了解老年原发性高血压晨峰现象对主要靶器官结构及功能的潜在损害。114例老年原发性高血压患者根据24h动态血压监测分为晨峰组和非晨峰组,均常规检查血脂谱,空腹血糖,放免法测定尿微量白蛋白,计算体重指数(BMI)、左室质量指数(LVMI)、颈总动脉(CCA-IMT)和颈内动脉内膜中层厚度(ICA-IMT)、心电图测量计算QT离散度(QTcd)。晨峰组的24h、白昼、夜间平均收缩压均显著高于非晨峰组动态血压监测水平(P<0.05),而且晨峰组的睡-谷晨峰变异幅度增高有统计学意义(P<0.05)。晨峰组的LVMI、CCA-IMT、ICA-IMT、QTcd和尿微量白蛋白指标均高于非晨峰组(P<0.01)。两组在BMI、血脂谱、血糖差异无统计学意义。清晨高血压是老年原发性高血压病的一个不可忽视的潜在危险因素。长期晨间血压负荷升高使得机体全天处于血压高负荷状态,更易使心肌重构肥厚和心电生理特征改变,增加心律失常发生率;加速动脉粥样硬化斑块形成。因此遏制老年原发性高血压患者的晨峰高反应是降压达标和减缓靶器官损害的关键环节。  相似文献   
37.
The specific movement demands of soccer that are linked to post-match recovery and readiness to train are unclear. Therefore, we examined the relationship between Global Positioning System (GPS) variables and the change (Δ; from baseline) in Creatine Kinase (CK) concentrations and peak power output (PPO; during the countermovement jump) at 24 h and 48 h post-match. Fifteen English Premier League reserve team players were examined over 1–4 matches. Measurements of CK and PPO were taken before (24 h prior to match-play) and after (+24 h and +48 h) each game during which movement demands were quantified using 10 Hz GPS data. High intensity distance covered (r = 0.386, p = 0.029; r = −0.349; p = 0.050), high intensity distance covered⋅min−1 (r = 0.365, p = 0.040; r = −0.364, p = 0.040), high speed running distance (r = 0.363, p = 0.041; r = −0.360, p = 0.043) and the number of sprints⋅min−1 (r = 0.410, p = 0.020; r = −0.368, p = 0.038) were significantly related to ΔCK and ΔPPO at +24 h post-match, respectively. No relationships were observed between any match variables and ΔCK and ΔPPO after +48 h of recovery. These findings highlight that high intensity match activities are related to ΔCK and ΔPPO in the 24 h, but not 48 h, following soccer match-play. Such information is likely of interest to those responsible for the design of soccer player’s training schedules in the days following a match.  相似文献   
38.
Tungsten (W) is cited as a candidate first-wall material in fusion reactors owing to its outstanding thermal properties and erosion resistance. An important issue is that the energetic isotopes of hydrogen, tritium (T) and deuterium (D) and helium (He) particles damage the surface of W in fusion reactors. He particles cause more notable damage than D or T because the binding energy of defects and He is larger than that of defects and D or T. In this study, well-annealed W specimens were implanted with 5 keV He ions at room temperature and irradiation dosages of 1.0 × 1020 and 2.5 × 1021 ions/m2. Then, thermal desorption spectroscopy analysis was performed by heating the samples to 1973 K at a ramping rate of 0.5 K/s. Thermal desorption of He in the sample irradiated with a low dosage occurred at 1400 and 1960 K, whereas that in the sample irradiated with a high dosage occurred at 740, 1050 and 1500 K. According to the microstructures observed using transmission electron microscopy, both peaks in the former case were attributed to He de-trapping from irradiation to nduced helium-vacancy clusters of different sizes, whereas the peaks in the latter case were attributed to He de-trapping from surface defects, irradiation-induced dislocation loops and tiny helium-vacancy clusters, respectively.  相似文献   
39.
At the synchrotron facility, Super Photon Ring – 8 GeV, in-situ X-ray diffraction during tensile deformation was conducted on ultrafine-grained Cu with a grain size of about 300 nm fabricated by equal-channel angular pressing. The diffraction profile was observed with the time resolution of about 1 s using multiple MYTHEN detectors, and the diffraction angle and the full-width at half-maximum of some Bragg peaks were determined using the pseudo-Voigt function. From the analysis of Bragg peaks, it was found out that there are microscopically three regions; elastic, plastic and transition regions. The 0.2% proof stress obtained from the stress–strain curve locates within the microscopic transition region. Microstrain was evaluated using the Williamson–Hall method and the dislocation density was also obtained from the microstrain. The dislocation density starts increasing before 0.2% proof stress, which is associated with dislocation bow-out and emission from grain boundaries. The Taylor relationship seems to be still satisfied after 0.2% proof stress.  相似文献   
40.

The electronic properties of an Al = 9 tilt grain boundary with segregated Na and Ca impurity atoms have been calculated by a first-principles pseudopotential method. The results show that the boundary expands and the charge density decreases significantly over the whole boundary by the segregation of Na and Ca, and there are no stronger bonds than those associated with metallic bonding in the boundary even with the impurities. It is concluded that the embrittlement promotion mechanism by Na or Ca segregation in the Al boundaries is one kind of 'decohesion model'.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号