全文获取类型
收费全文 | 23735篇 |
免费 | 189篇 |
国内免费 | 1篇 |
出版年
2023年 | 35篇 |
2022年 | 33篇 |
2021年 | 54篇 |
2020年 | 83篇 |
2019年 | 108篇 |
2018年 | 3563篇 |
2017年 | 2907篇 |
2016年 | 2387篇 |
2015年 | 272篇 |
2014年 | 164篇 |
2013年 | 454篇 |
2012年 | 738篇 |
2011年 | 2567篇 |
2010年 | 2611篇 |
2009年 | 1576篇 |
2008年 | 1850篇 |
2007年 | 2300篇 |
2006年 | 175篇 |
2005年 | 319篇 |
2004年 | 290篇 |
2003年 | 228篇 |
2002年 | 169篇 |
2001年 | 90篇 |
2000年 | 101篇 |
1999年 | 53篇 |
1998年 | 60篇 |
1997年 | 52篇 |
1996年 | 48篇 |
1995年 | 42篇 |
1994年 | 42篇 |
1993年 | 24篇 |
1992年 | 28篇 |
1991年 | 28篇 |
1990年 | 26篇 |
1989年 | 21篇 |
1988年 | 21篇 |
1987年 | 21篇 |
1986年 | 17篇 |
1985年 | 35篇 |
1984年 | 22篇 |
1983年 | 19篇 |
1982年 | 28篇 |
1981年 | 23篇 |
1980年 | 18篇 |
1979年 | 25篇 |
1978年 | 17篇 |
1977年 | 23篇 |
1975年 | 18篇 |
1974年 | 19篇 |
1973年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
Aging and visual marking: selective deficits for moving stimuli 总被引:1,自引:0,他引:1
The selective processing of new visual information can be facilitated by the top-down inhibition of old stimuli already in the visual field, a capacity-limited process termed visual marking (D. G. Watson & G. W. Humphreys, 1997). Three experiments assessed the effects of aging on visual marking using stationary (Experiment 1) and moving (Experiments 2 and 3) items. For young participants, visual marking was observed in all experiments. For older participants, visual marking was observed only with stationary items. The results are not consistent with any simple account of general age-related decrements and provide further support for the deployment of different methods of visual marking depending on the properties of the old items and the current task demands. 相似文献
192.
This research extends the use of P. B. Baltes and M. M. Baltes's (1990) theory of selective optimization with compensation (SOC) in an effort to conceptually integrate the adaptational behaviors of 248 older adults with disability arising from osteoarthritis. The authors also studied the relationship of SOC to age, illness variables, disability, illness perceptions, and support. The results highlight the variability and plasticity of older adults' efforts to manage disability, with most efforts aimed at compensation and optimization rather than selection. The benefit of using SOC to study adaptation to chronic illness and disability is discussed. 相似文献
193.
Although not previously addressed by researchers of spatial cognition or affect, the combination of spatial and affective information is essential for many approach and avoidance behaviors, and thus for survival. We provide the first evidence that through incidental experience, people form representations that capture correlations between affective and spatial information. Participants were able to do so even when the correlation was weak, they were not told to look for the correlation, and the stimuli varied on multiple other dimensions besides valence. In addition, people were more sensitive to the presented correlation when stimuli were negative than when they were positive. This asymmetry in representation may stem from underlying differences in the activation functions for positive and negative hedonic information processing. 相似文献
194.
Buchanan A Califano A Kahn J McPherson E Robertson J Brody B 《Kennedy Institute of Ethics journal》2002,12(1):1-15
Pharmacogenetics offers the prospect of an era of safer and more effective drugs, as well as more individualized use of drug therapies. Before the benefits of pharmacogenetics can be realized, the ethical issues that arise in research and clinical application of pharmacogenetic technologies must be addressed. The ethical issues raised by pharmacogenetics can be addressed under six headings: (1) regulatory oversight, (2) confidentiality and privacy, (3) informed consent, (4) availability of drugs, (5) access, and (6) clinicians' changing responsibilities in the era of pharmacogenetic medicine. We analyze each of these categories of ethical issues and provide policy approaches for addressing them. 相似文献
195.
Evidence for preserved representations in change blindness 总被引:2,自引:0,他引:2
People often fail to detect large changes to scenes, provided that the changes occur during a visual disruption. This phenomenon, known as "change blindness," occurs both in the laboratory and in real-world situations in which changes occur unexpectedly. The pervasiveness of the inability to detect changes is consistent with the theoretical notion that we internally represent relatively little information from our visual world from one glance at a scene to the next. However, evidence for change blindness does not necessarily imply the absence of such a representation---people could also miss changes if they fail to compare an existing representation of the pre-change scene to the post-change scene. In three experiments, we show that people often do have a representation of some aspects of the pre-change scene even when they fail to report the change. And, in fact, they appear to "discover" this memory and can explicitly report details of a changed object in response to probing questions. The results of these real-world change detection studies are discussed in the context of broader claims about change blindness. 相似文献
196.
Chapman E 《Journal of genetic counseling》2002,11(5):351-367
This paper examines some of the ethical dilemmas that arise when testing for the late onset, untreatable condition of Huntington disease (HD) specifically now that technology allows us to test younger generations of the family for the mutant gene. Drawing on interview data from families with Huntington disease, the reactions to testing and perceived impact on other family members are considered. These are discussed in the light of the possible lowering of the age of test applicants. This potentially raises problems for a younger generation as they are confronted with reproductive decisions that the older generation did not have to face. It also means that individuals have the prospect of living with knowledge of a future illness for much longer. 相似文献
197.
Numerous previous investigators have explained species differences in spatial memory performance in terms of differences
in foraging ecology. In three experiments we attempted to extend these findings by examining the extent to which the spatial
memory performance of echidnas (or "spiny anteaters") can be understood in terms of the spatio-temporal distribution of their
prey (ants and termites). This is a species and a foraging situation that have not been examined in this way before. Echidnas
were better able to learn to avoid a previously rewarding location (to "win-shift") than to learn to return to a previously
rewarding location (to "win-stay"), at short retention intervals, but were unable to learn either of these strategies at retention
intervals of 90 min. The short retention interval results support the ecological hypothesis, but the long retention interval
results do not.
Electronic Publication 相似文献
198.
Recall is typically better for emotional than for neutral stimuli. This enhancement is believed to rely on limbic regions. Memory is also better for neutral stimuli embedded in an emotional context. The neural substrate supporting this effect has not been thoroughly investigated but may include frontal lobe, as well as limbic circuits. Alzheimer's disease (AD) results in atrophy of limbic structures, whereas normal aging relatively spares limbic regions but affects prefrontal areas. The authors hypothesized that AD would reduce all enhancement effects, whereas aging would disproportionately affect enhancement based on emotional context. The results confirmed the authors' hypotheses: Young and older adults, but not AD patients, showed better memory for emotional versus neutral pictures and words. Older adults and AD patients showed no benefit from emotional context, whereas young adults remembered more items embedded in an emotional versus neutral context. 相似文献
199.
The dual-process model of recognition memory proposed by Jacoby (1991; see also Mandler, 1980) postulates the existence of two independent components of recognition memory: a conscious retrieval process (recollection) and an automatic component ( familiarity). Older adults appear to be impaired in recollection, but findings with respect to familiarity have been mixed. Studies of the brain bases of these components, using neurological patients, have also been inconclusive. We examined recollection and familiarity, using the process dissociation procedure, in older adults characterized on the basis of both their frontal and their medial temporal lobe function. Findings suggest that only some older adults, depending on their neuropsychological status, are impaired in recollection and/or familiarity: Recollection seems to involve both frontal and medial temporal lobe function, whereas familiarity appears to be dependent only on function associated with the medial temporal lobes. 相似文献
200.
O'Connor TS McCarroll-Butler P Meakes E Davis A Jadad A 《The journal of pastoral care & counseling : JPCC》2002,56(3):227-232
Using computer technology to identify the term "spiritual," these researchers present results of the 2306 citations and compare five criteria discovered with research reported in four pastoral counseling journals. The authors note the limitations of such a search and the possible implications of the findings for health care ministry. 相似文献