全文获取类型
收费全文 | 2868篇 |
免费 | 296篇 |
国内免费 | 669篇 |
专业分类
3833篇 |
出版年
2024年 | 5篇 |
2023年 | 59篇 |
2022年 | 64篇 |
2021年 | 102篇 |
2020年 | 125篇 |
2019年 | 118篇 |
2018年 | 135篇 |
2017年 | 128篇 |
2016年 | 140篇 |
2015年 | 97篇 |
2014年 | 96篇 |
2013年 | 261篇 |
2012年 | 168篇 |
2011年 | 218篇 |
2010年 | 194篇 |
2009年 | 189篇 |
2008年 | 216篇 |
2007年 | 284篇 |
2006年 | 244篇 |
2005年 | 234篇 |
2004年 | 168篇 |
2003年 | 115篇 |
2002年 | 69篇 |
2001年 | 47篇 |
2000年 | 45篇 |
1999年 | 43篇 |
1998年 | 37篇 |
1997年 | 28篇 |
1996年 | 18篇 |
1995年 | 22篇 |
1994年 | 24篇 |
1993年 | 14篇 |
1992年 | 10篇 |
1991年 | 12篇 |
1990年 | 10篇 |
1989年 | 15篇 |
1988年 | 6篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
排序方式: 共有3833条查询结果,搜索用时 0 毫秒
981.
We investigated three issues with respect to the long-term serial recall of adults. First, retention interval was manipulated to obtain uncontaminated measures of long-term serial recall. Second, we compared serial recall of concrete and abstract nouns to determine how these materials might interact with various learning strategies over time. Third, control group participants were asked to describe the learning strategies used, allowing a comparison of technical mnemonic techniques with the spontaneously generated strategies of adults. We found that the delayed recall performance of participants who spontaneously used organizational or imagery-based strategies was comparable to that of those instructed in the method of loci and pegword technique. Word concreteness did not interact with any other variable. These results are discussed with regard to their implications for serial learning in educational settings. 相似文献
982.
Observers made systematic heading judgments in two experiments simulating their translation through an environment with only two trees. When those trees converged or decelerated apart, observers tended to follow the invariant information and make heading judgments outside the near member of the pair. When those trees accelerated apart, however, observers tended to follow the heuristic information and make judgments outside the far member, although this result was tempered by the angular separation between the trees and their relative acceleration. The simultaneous existence and use of invariants and heuristics are discussed in terms of different metatheoretical approaches to perception. 相似文献
983.
In this study, we examine the suitability of a relatively new imaging technique, arterial spin labeled perfusion imaging, for the study of continuous, gradual changes in neural activity. Unlike BOLD imaging, the perfusion signal is stable over long time-scales, allowing for accurate assessment of continuous performance. In addition, perfusion fMRI provides an absolute measure of blood flow so signal changes can be interpreted without reference to a baseline. The task we used was the serial response time task, a sequence learning task. Our results show reliable correlations between performance improvements and decreases in blood flow in premotor cortex and the inferior parietal lobe, supporting the model that learning procedures that increase efficiency of processing will be reflected in lower metabolic needs in tissues that support such processes. More generally, our results show that perfusion fMRI may be applied to the study of mental operations that produce gradual changes in neural activity. 相似文献
984.
Thomas LE Ambinder MS Hsieh B Levinthal B Crowell JA Irwin DE Kramer AF Lleras A Simons DJ Wang RF 《Psychonomic bulletin & review》2006,13(5):891-895
Inhibition of return (IOR) has long been viewed as a foraging facilitator in visual search. We investigated the contribution
of IOR in a task that approximates natural foraging more closely than typical visual search tasks. Participants in a fully
immersive virtual reality environment manually searched an array of leaves for a hidden piece of fruit, using a wand to select
and examine each leaf location. Search was slower than in typical IOR paradigms, taking seconds instead of a few hundred milliseconds.
Participants also made a speeded response when they detected a flashing leaf that either was or was not in a previously searched
location. Responses were slower when the flashing leaf was in a previously searched location than when it was in an unvisited
location. These results generalize IOR to an approximation of a naturalistic visual search setting and support the hypothesis
that IOR can facilitate foraging. The experiment also constitutes the first use of a fully immersive virtual reality display
in the study of IOR. 相似文献
985.
Clark and Beck (1999) and Williams et al. (1997) have come up with quite different conclusions regarding which cognitive processes are most affected by negative self-schemata and negative knowledge structures. In order to increase the understanding of differences in effortful and automatic processing in depression, we compared never depressed (ND), previously depressed (PD) and clinically depressed (CD) individuals on free recall, recognition and fabrication of positive and negative self-statements. The results showed that: (i) overall NDs and PDs recalled more positive self-statements than CDs, whereas CDs correctly recognized more negative self-statements than NDs and PDs; and (ii) CDs and PDs fabricated more negative than positive self-statements, whereas no difference was obtained for NDs. The results seem to be in line with Clark and Beck's suggestions. However, there are several aspects of the present findings that make the picture more complicated. 相似文献
986.
Wang RF 《Perception & psychophysics》2004,66(1):68-76
Spatial updating has been shown to occur automatically and operate on both real and imagined environments. In three experiments, we compared spatial updating in real and imagined environments and examined when automatic spatial updating occurs. Participants learned the locations of real objects in a room and imagined being in their kitchens. They turned to face either the kitchen or the room targets and pointed to the targets before and after turning. Although objects in the real environment were automatically updated when the participants turned in the imagined environment, targets in the imagined environment were not automatically updated when the participants turned in the real environment. However, explicit spatial updating of imagined environments was as efficient as that of real environments. Automatic updating of the real objects required perceptual experience of these targets, either visually or by touch, and did not occur when the targets were described verbally. Implications for spatial cognition research are discussed. 相似文献
987.
Nilam?RamEmail author Sy-Miin?Chow Ryan?P.?Bowles Lijuan?Wang Kevin?Grimm Frank?Fujita John?R.?Nesselroade 《Psychometrika》2005,70(4):773-790
Weekly cycles in emotion were examined by combining item response modeling and spectral analysis approaches in an analysis
of 179 college students' reports of daily emotions experienced over 7 weeks. We addressed the measurement of emotion using
an item response model. Spectral analysis and multilevel sinusoidal models were used to identify interindividual differences
in intraindividual cyclic change. Simulations and incomplete data designs were used to examine how well this combination of
analysis techniques might work when applied to other practical data problems. Empirically, we found systematic individual
differences in the extent to which individuals' emotions follow a weekly cycle, and in how such cycles are exhibited. Weekly
cycles accounted for very little variance in day to day emotions at the individual level. Analytically, we illustrate how
measurement, change, and interindividual difference models from different traditions may be combined in a practical manner
to describe some of the complexities of human behavior.
The authors gratefully acknowledge the support provided by grant T32 AG20500 from the National Institute on Aging in the preparation
of this article. Special thanks to those at the Institute for Developmental and Health Research Methodology at the University
of Virginia and to Paul De Boeck and the reviewers for helpful comments on earlier versions of this work. 相似文献
988.
<维摩诘经>是印度早期大乘佛教的重要经典,在南北朝和隋唐时期广为流传,在佛教般若思想的发展中占有重要地位.该经蕴含着丰富的净土思想,明确提出了"心净则佛土净"这一著名命题.本文从菩萨取净土之目的与方法的角度,认为<维摩诘经>中菩萨取净土的目的是度化调伏众生,此即为"众生之类是菩萨佛土"的内含意蕴,还阐述分析了建立净佛国土之净土行和"心净则佛土净"思想. 相似文献
989.
Two types of mechanisms have dominated theoretical accounts of efficient visual search. The first are bottom-up processes related to the characteristics of retinotopic feature maps. The second are top-down mechanisms related to feature selection. To expose the potential involvement of other mechanisms, we introduce a new search paradigm whereby a target is defined only in a context-dependent manner by multiple conjunctions of feature dimensions. Because targets in a multiconjunction task cannot be distinguished from distractors either by bottom-up guidance or top-down guidance, current theories of visual search predict inefficient search. While inefficient search does occur for the multiple conjunctions of orientation with color or luminance, we find efficient search for multiple conjunctions of luminance/size, luminance/shape, and luminance/topology. We also show that repeated presentations of either targets or a set of distractors result in much faster performance and that bottom-up feature extraction and top-down selection cannot account for efficient search on their own. In light of this, we discuss the possible role of perceptual organization in visual search. Furthermore, multiconjunction search could provide a new method for investigating perceptual grouping in visual search. 相似文献
990.
Activation of group II metabotropic glutamate receptors induces depotentiation in amygdala slices and reduces fear-potentiated startle in rats 总被引:3,自引:0,他引:3 下载免费PDF全文
Lin CH Lee CC Huang YC Wang SJ Gean PW 《Learning & memory (Cold Spring Harbor, N.Y.)》2005,12(2):130-137
There is a close correlation between long-term potentiation (LTP) in the synapses of lateral amygdala (LA) and fear conditioning in animals. We predict that reversal of LTP (depotentiation) in this area of the brain may ameliorate conditioned fear. Activation of group II metabotropic glutamate receptors (mGluR II) with DCG-IV induces depotentiation in the LA. The induction of depotentiation is independent of NMDA receptors, L-type Ca++ channels, and calcineurin activity, but requires presynaptic activity and extracellular Ca++. (2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine (DCG-IV) depotentiation is accompanied by a decrease in the frequency but not the amplitude of miniature excitatory post-synaptic currents (mEPSCs) and could be mimicked by endogenously released glutamate. DCG-IV inhibited the release of glutamate evoked by 4-AP but not that evoked by ionomycin, suggesting that the effect of DCG-IV is not mediated by an action downstream of Ca++ entry. Intra-amygdala infusion of mGluR II agonist blocks the consolidation of fear memory measured with fear-potentiated startle. Taken together, the present results characterize the properties of DCG-IV depotentiation and reveal a close parallel between depotentiation in the amygdala slice and the reduction of conditioned fear in animals. 相似文献