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71.
本研究选择北京地区幼儿园3岁、4岁、5岁儿童各31、48、33名, 采用单部件意识测验和部件位置及功能意识测验系统探查了学龄前儿童的正字法意识各个层面的发展状况。单部件意识测验包括部件替换、部件缺失和部件旋转三个部分; 部件位置及功能意识测验分为假字和非字两个部分, 而非字又包括两形非字和形声非字。结果发现单部件意识测验中, 5岁组儿童在部件替换水平上的得分显著高于3岁组儿童, 而3岁组与4岁组、4岁组与5岁组儿童之间无显著差异; 部件缺失和部件旋转水平上, 三个年龄段的儿童的得分表现出明显的增长趋势。部件位置及功能意识测验中, 假字得分在三个年龄段之间无显著差异; 非字得分随年龄增长显著提高。这些结果表明, 单部件意识在学前期处于不断发展的阶段, 其中对部件替换的非字的拒绝能力发展较早, 部件缺失和部件旋转非字的拒绝能力发展较晚; 部件位置及功能意识在学前期已经开始发展, 3岁儿童已经具有假字符合正字法规则的认识, 但对非字违反部件位置合法性和功能完整性的认识直到4岁左右才开始萌芽, 5岁还未成熟。 相似文献
72.
Tae Wook Heo Yi Wang Saswata Bhattacharya Xin Sun Shenyang Hu Long-Qing Chen 《Philosophical Magazine Letters》2013,93(2):110-121
We propose a phase-field model for modeling microstructure evolution during deformation twinning. The order parameters are proportional to the shear strains defined in terms of twin plane orientations and twinning directions. Using a face-centered cubic Al as an example, the deformation energy as a function of shear strain is obtained using first-principle calculations. The gradient energy coefficients are fitted to the twin boundary energies along the twinning planes and to the dislocation core energies along the directions that are perpendicular to the twinning planes. The elastic strain energy of a twinned structure is included using the Khachaturyan's elastic theory. We simulated the twinning process and microstructure evolution under a number of fixed deformations and predicted the twinning plane orientations and microstructures. 相似文献
73.
A highly supersaturated nanocrystalline Cr–25?wt% Zr alloy has been prepared by mechanical alloying of elemental crystalline powders. High-purity powders of Cr and Zr were milled for up to 20?h. The development of the microstructure was investigated by X-ray diffraction (XRD) and scanning electron microscopy. XRD patterns confirmed complete alloying of the Zr and Cr. The contribution of grain boundaries, the chemical potential of a solute atom induced by dislocations, and the elastic strain energy arising from the different sizes of Cr and Zr atoms have been calculated. The alloy formation is discussed with respect to the thermodynamic conditions of the material. The role of internal strains and stored enthalpies by dislocations on solute atoms is the major mechanical driving force for alloying and this is critically assessed in this article. 相似文献
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76.
利用有限的认知资源应对多变的环境刺激,选择性注意和情绪加工一个重要的共同机制是优先化关键信息的加工。尽管情绪性刺激(特别是威胁刺激)能够影响注意资源的分配,但一些关键脑区(如杏仁核)的对情绪性刺激的加工是自动化过程还是受到注意调节一直是个有争议的问题。最新的结合高时间分辨率和高空间分辨率的神经生理记录研究表明,情绪加工的重要核团,杏仁核,对情绪性刺激的加工包含早期快速的不依赖于注意资源和认知加工负荷的自动化加工成分和晚期受到额-顶叶皮层自上而下的注意调控成分,这种功能整合证实杏仁核情绪性加工存在并行的皮层下和皮层通路。 相似文献
77.
We show that perceived size of visual stimuli can be altered by matches between the contents of visual short-term memory and stimuli in the scene. Observers were presented with a colour cue (to hold in working memory or to merely identify) and subsequently had to indicate which of the two different-coloured objects presented simultaneously on the screen appeared bigger (or smaller). One of the two objects for size judgements had the same colour as the cue (matching stimulus) and the other did not (mismatching stimulus). Perceived object size was decreased by the reappearance of the recently seen cue, as there were more size judgement errors on trials where the matching stimulus was physically bigger (relative to the mismatching stimulus) than on trials where the matching stimulus was physically smaller. The effect occurred regardless of whether the visual cue was actively maintained in working memory or was merely identified. The effect was unlikely generated by the allocation of attention, because shifting attention to a visual stimulus actually increased its perceived size. The findings suggest that visual short-term memory, whether explicit or implicit, can decrease the perceived size of subsequent visual stimuli. 相似文献
78.
Colin Camerer Yi Xin Clarice Zhao 《Journal of the experimental analysis of behavior》2024,121(1):108-122
This article applies a two-process “neural autopilot” model to field data. The autopilot model hypothesizes that habitual choice occurs when the reward from a behavior has low numerical “doubt” (i.e., reward prediction errors are small). The model toggles between repeating a previous choice (habit) when doubt is low and making a goal-directed choice when doubt is high. The model has ingredients established in animal learning and cognitive neuroscience and is simple enough to make nonobvious predictions. In two empirical applications, we fit the model to field data on purchases of canned tuna and posting on the Chinese social media site Weibo. This style of modeling is called “structural” because there is a theoretical model of how different variables influence choices by agents (the “structure”), which tightly restricts how hidden variables lead to observed choices. There is empirical support for the model, more strongly for tuna purchases than for Weibo posting, relative to a baseline “reduced-form” model in which current choices are correlated with past choices without a mechanistic (structural) explanation. An interesting set of predictions can also be derived about how consumers react to different kinds of changes in prices and qualities of goods (this is called “counterfactual analysis”). 相似文献
79.
厌腻感是指消费者对连续或过量消费同一产品或服务的效用感、享乐感或满意度下降, 负面感知逐步抑制正面感知的主观情绪体验。为缓解或防止厌腻感的产生, 消费者会采取品牌转换、多样化寻求、控制消费周期等行为, 因此厌腻感已成为企业或店铺培养顾客忠诚的主要障碍。国外文献分别从厌腻感的生成过程、功能反应、知觉状态和属性感知等方面, 划分厌腻类型; 剖析了厌腻感生成的享乐适应、边际效用递减、认知失调以及最佳刺激水平等理论原理及机理; 探讨了生理厌腻感和心理厌腻感生成的诱发因素及影响效应; 验证了外部因素和个体因素的调节作用; 同时探讨了消费者缓解或防止厌腻感的主要策略及行为反应。最后对现有文献的研究思路、特点和不足进行了评述, 提出了未来研究方向。 相似文献
80.
本工作对两例先天性无痛症患者对于致痛性强刺激的知觉和反应进行了研究(例1女,10岁,例2男,13岁)。对照组为20例正常儿童,性别和年龄均与患儿相匹配。 结果:1),生活中痛:两例患儿均无(包括痛感觉和痛反应)。2)实验性痛:①痛感觉:两例患儿均无;②“痛”反应:例1有“痛”反应(脉搏和呼吸的变化以及行为反应明显,大致与正常儿童相似)。例2无“痛”反应(脉搏和呼吸的变化轻微,无行为反应,与正常儿童不同)。 由结果看来,先天性无痛症患者似乎可分为两种类型:不完全型(如同例1)和完全型(如同例2)。存在有“痛”反应而无痛感觉的无痛症患者。 本工作结果从另一侧面为痛的两成分学说提供了依据。 相似文献