全文获取类型
收费全文 | 601篇 |
免费 | 88篇 |
国内免费 | 127篇 |
专业分类
816篇 |
出版年
2024年 | 4篇 |
2023年 | 13篇 |
2022年 | 21篇 |
2021年 | 27篇 |
2020年 | 25篇 |
2019年 | 29篇 |
2018年 | 25篇 |
2017年 | 42篇 |
2016年 | 35篇 |
2015年 | 27篇 |
2014年 | 29篇 |
2013年 | 58篇 |
2012年 | 43篇 |
2011年 | 48篇 |
2010年 | 51篇 |
2009年 | 38篇 |
2008年 | 45篇 |
2007年 | 52篇 |
2006年 | 47篇 |
2005年 | 31篇 |
2004年 | 20篇 |
2003年 | 13篇 |
2002年 | 15篇 |
2001年 | 5篇 |
2000年 | 15篇 |
1999年 | 10篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 2篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1981年 | 6篇 |
1979年 | 1篇 |
排序方式: 共有816条查询结果,搜索用时 0 毫秒
171.
本文探讨与分析了原始及部派佛教的"六识"说,尤其从心识与五蕴、与十二处、与十八界、与心所、与其他诸法、与四缘的联系上,指出"六识"说存在的局限,而正是由于这些局限,才必然导致更为严密、周详,尤其非心理主义的唯识学的"八识"说的出现. 相似文献
172.
The PREG model of question asking assumes that questions emerge when there is cognitive disequilibrium, as in the case of contradictions, obstacles, and anomalies. Participants read illustrated texts about everyday devices (e.g., a cylinder lock) and then were placed in cognitive disequilibrium through a breakdown scenario (e.g., the key turns but the bolt does not move). The participants asked questions when given the breakdown scenario, and an eyetracker recorded their fixations. As was predicted, deep comprehenders asked better questions and fixated on device components that explained the malfunction. The eye fixations were examined before, during, and after the participants' questions in order to trace the occurrence and timing of convergence on faults, causal reasoning, and other cognitive processes. 相似文献
173.
174.
Multiple attributes of a visual array are often more efficiently processed when they are attributes of a single object than when they are attributes of different objects—a pattern reflecting the limitations of object attention. This study used psychophysical methods to evaluate the object attention limitations in the report of attributes (orientation and phase) computed early in visual analysis for spatially separated objects. These limitations had large effects on dual-object report thresholds when different judgments were required for the two objects (orientation for one object and phase for the other), but the effects were small or nonexistent when the same judgment was made about both objects. Judgment consistency reduced or eliminated the expression of object attention deficits. Thus, the deficits in dual-object report reflect both division of attention over objects and the calculation of independent reference or judgment operations. Dual-object deficits, when they occurred, were substantial in displays with external noise masks. Smaller effects were observed in clear displays, even when difficulty was equated by stimulus contrast. Thus, the primary consequence of object attention is the exclusion of external noise, or mask suppression, and enhancement of the stimulus in clear displays is a secondary consequence. 相似文献
175.
Left or right keypresses to a relevant stimulus dimension are faster when the stimulus location, although irrelevant, corresponds with that of the response than when it does not. This phenomenon, called the Simon effect, persisted across 1,800 trials of practice, although its magnitude was reduced. Practice with the relevant stimulus dimension presented at a centered location had little influence on the magnitude of the Simon effect when irrelevant location was varied subsequently, and practice with location irrelevant prior to performing with location relevant slowed responses. After practice responding to stimulus location with an incompatible spatial mapping, the Simon effect was reversed (i.e., responses were slower when stimulus location corresponded with response location) when location was made irrelevant. When the response keys were labeled according to the relevant stimulus dimension (the Hedge and Marsh [1975] task variation), this reversal from practice with a spatially incompatible mapping was found for both the congruent and the incongruent relevant stimulus-response mappings. Thus, task-defined associations between stimulus location and response location affect performance when location is changed from relevant to irrelevant, apparently through producing automatic activation of the previously associated response. 相似文献
176.
177.
Hyeon Son Yun-Fei Lu Min Zhuo Ottavio Arancio Eric R. Kandel Robert D. Hawkins 《Learning & memory (Cold Spring Harbor, N.Y.)》1998,5(3):231-245
Previous results have suggested that cGMP is involved in hippocampal long-term potentiation (LTP), perhaps as the presynaptic effector of a retrograde messenger. However, other studies have failed to replicate some of those results, making the role of cGMP uncertain. We therefore reexamined this question and identified several variables that can affect the contribution of cGMP. First, brief perfusion with 8-Br–cGMP before weak tetanic stimulation produced long-lasting potentiation in the CA1 region of hippocampal slices, but more prolonged perfusion with 8-Br–cGMP before the tetanus did not produce long-lasting potentiation. Second, the activity-dependent long-lasting potentiation by cGMP analogs was reduced when NMDA receptors were completely blocked, indicating that NMDA receptor activation contributes to, but is not required for, the potentiation. The amount of reduction of the potentiation differed with different protocols, and in some cases could be complete. Third, LTP produced by strong tetanic stimulation in the stratum radiatum of CA1 (which expresses eNOS) was blocked by inhibitors of soluble guanylyl cyclase or cGMP-dependent protein kinase, but LTP in the stratum oriens (which does not express eNOS) was not. The results of these experiments should help to explain some of the discrepant findings from previous studies, and, in addition, may provide insights into the mechanisms and functional role of the cGMP-dependent component of LTP. 相似文献
178.
Selective Abolition of the NMDA Component of Long-Term Potentiation in Mice Lacking mGluR5 总被引:6,自引:0,他引:6 下载免费PDF全文
Zhengping Jia YouMing Lu Jeff Henderson Franco Taverna Carmelo Romano Wanda Abramow-Newerly J. Martin Wojtowicz John Roder 《Learning & memory (Cold Spring Harbor, N.Y.)》1998,5(4):331-343
The mechanisms underlying the differential expression of long-term potentiation (LTP) by AMPA and NMDA receptors, are unknown, but could involve G-protein-linked metabotropic glutamate receptors. To investigate this hypothesis we created mutant mice that expressed no metabotropic glutamate receptor 5 (mGluR5), but showed normal development. In an earlier study of these mice we analyzed field-excitatory postsynaptic potential (fEPSPs) in CA1 region of the hippocampus and found a small decrease; possibly arising from changes in the NMDAR-mediated component of synaptic transmission. In the present study we used whole-cell patch clamp recordings of evoked excitatory postsynaptic currents (EPSCs) in CA1 pyramidal neurons to identify the AMPAR- and NMDAR-mediated components of LTP. Recordings from control mice following tetanus, or agonist application (IS, 3R-1-amino-cyclopentane 1,3-dicarboxylic acid) (ACPD), revealed equal enhancement of the AMPA and NMDA receptor-mediated components. In contrast, CA1 neurons from mGluR5-deficient mice showed a complete loss of the NMDA-receptor-mediated component of LTP (LTPNMDA), but normal LTP of the AMPA-receptor-mediated component (LTPAMPA). This selective loss of LTPNMDA was seen in three different genotypic backgrounds and was apparent at all holding potentials (−70 mV to +20 mV). Furthermore, the LTPNMDA deficit in mGluR5 mutant mice could be rescued by stimulating protein kinase C (PKC) with 4β-phorbol-12,13-dibutyrate (PDBu). These results suggest that PKC may couple the postsynaptic mGluR5 to the NMDA-receptor potentiation during LTP, and that this signaling mechanism is distinct from LTPAMPA. Differential enhancement of AMPAR and NMDA receptors by mGluR5 also supports a postsynaptic locus for LTP. 相似文献
179.
180.
本文是对皮亚杰“物体守恒”实验的验证。从而探讨了4—9岁儿童在形成守恒概念中的逻辑思惟发展过程,为编制智力测验量表提供了有关参考数据。 相似文献