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131.
Humans are limited in their ability to maintain multiple attentional foci. In attentive tracking of moving objects, performance
declines as the number of tracked targets increases. Previous studies have interpreted such reduction in terms of a limit
in the number of attentional foci. However, increasing the number of targets usually reduces spatial separation among different
targets. In this study, we examine the role of target spatial separation in maintaining multiple attentional foci. Results
from a multiple-object tracking task show that tracking accuracy deteriorates as the spatial separation between targets decreases.
We propose that local interaction between nearby attentional foci modulates the resolution of attention, and that capacity
limitation from attentive tracking originates in part from limitations in maintaining critical spacing among multiple attentional
foci. These findings are consistent with the hypothesis that tracking performance is limited not primarily by a number of
locations, but by factors such as the spacing and speed of the targets and distractors. 相似文献
132.
Wang Z Pan Y Li W Jiang H Chatzimanolis L Chang J Gong Z Liu L 《Learning & memory (Cold Spring Harbor, N.Y.)》2008,15(3):133-142
The role of the foraging (for) gene, which encodes a cyclic guanosine-3',5'-monophosphate (cGMP)-dependent protein kinase (PKG), in food-search behavior in Drosophila has been intensively studied. However, its functions in other complex behaviors have not been well-characterized. Here, we show experimentally in Drosophila that the for gene is required in the operant visual learning paradigm. Visual pattern memory was normal in a natural variant rover (for(R)) but was impaired in another natural variant sitter (for(S)), which has a lower PKG level. Memory defects in for(S) flies could be rescued by either constitutive or adult-limited expression of for in the fan-shaped body. Interestingly, we showed that such rescue also occurred when for was expressed in the ellipsoid body. Additionally, expression of for in the fifth layer of the fan-shaped body restored sufficient memory for the pattern parameter "elevation" but not for "contour orientation," whereas expression of for in the ellipsoid body restored sufficient memory for both parameters. Our study defines a Drosophila model for further understanding the role of cGMP-PKG signaling in associative learning/memory and the neural circuit underlying this for-dependent visual pattern memory. 相似文献
133.
对“家属签字”制度的立法思考 总被引:1,自引:0,他引:1
邵将 《医学与哲学(人文社会医学版)》2008,29(5):42-44
李丽云悲剧的发生,使《医疗机构管理条例》第三十三条规定的“家属签字”制度成为公众及法律界人士关注的焦点。“家属签字”制度受到道德和法律的双重拷问。从“家属签字”制度中潜在的法律推定出发,对“家属签字”制度的正当性依据、“特殊情况”下对患者的求生推定等六方面问题做些有益探讨,以期完善我国医疗管理法律法规。 相似文献
134.
创新思维中原型激活促发顿悟的认知神经机制 总被引:1,自引:0,他引:1
创造性是人类智能的高级表现, 创新思维则是个体创造性的核心过程。我们以创造性问题解决中的顿悟过程为研究对象, 提出并验证了创新思维中原型激活促发顿悟的理论构想; 综合运用事件相关电位(ERP)和功能性核磁共振(fMRI)的技术优势, 初步揭示了原型激活促发顿悟的大脑机制。具体表现为, 楔前叶的激活可能与原型激活和关键信息提取有关; 左侧额下回/额中回的激活可能与与思维定势打破和新异联结形成有关; 同时研究也表明大脑的特定准备状态(额中回/扣带前回的激活)对顿悟的产生有积极的促进作用。 相似文献
135.
136.
大学生因特网成瘾障碍的研究 总被引:12,自引:1,他引:11
本研究根据目前广泛认可的因特网成瘾障碍(Internet Addiction Disorder,IAD)诊断标准自编问卷,调查了上海市6所高校370名大学生的上网情况。结果表明:(1)自编问卷质量的各指标皆良好,问卷具有较好的稳定性和准确性。(2)上海市大学生IAD的发生率大约为8.1%。(3)男生比女生、理科比文科、大二年级比其它年级的学生陷入网络的程度深。(4)上网者每周的上网时间、使用网络工具的数量、上网动机的数量与使用网络的程度相关。(5)IAD者在网络使用的特点上明显不同于非IAD者(N-IAD者)。 相似文献
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140.
A complete understanding of visual phonetic perception (lipreading) requires linking perceptual effects to physical stimulus properties. However, the talking face is a highly complex stimulus, affording innumerable possible physical measurements. In the search for isomorphism between stimulus properties and phoneticeffects, second-order isomorphism was examined between theperceptual similarities of video-recorded perceptually identified speech syllables and the physical similarities among the stimuli. Four talkers produced the stimulus syllables comprising 23 initial consonants followed by one of three vowels. Six normal-hearing participants identified the syllables in a visual-only condition. Perceptual stimulus dissimilarity was quantified using the Euclidean distances between stimuli in perceptual spaces obtained via multidimensional scaling. Physical stimulus dissimilarity was quantified using face points recorded in three dimensions by an optical motion capture system. The variance accounted for in the relationship between the perceptual and the physical dissimilarities was evaluated using both the raw dissimilarities and the weighted dissimilarities. With weighting and the full set of 3-D optical data, the variance accounted for ranged between 46% and 66% across talkers and between 49% and 64% across vowels. The robust second-order relationship between the sparse 3-D point representation of visible speech and the perceptual effects suggests that the 3-D point representation is a viable basis for controlled studies of first-order relationships between visual phonetic perception and physical stimulus attributes. 相似文献