全文获取类型
收费全文 | 2306篇 |
免费 | 202篇 |
国内免费 | 342篇 |
出版年
2024年 | 10篇 |
2023年 | 38篇 |
2022年 | 58篇 |
2021年 | 81篇 |
2020年 | 125篇 |
2019年 | 137篇 |
2018年 | 138篇 |
2017年 | 125篇 |
2016年 | 103篇 |
2015年 | 83篇 |
2014年 | 131篇 |
2013年 | 287篇 |
2012年 | 59篇 |
2011年 | 109篇 |
2010年 | 82篇 |
2009年 | 108篇 |
2008年 | 137篇 |
2007年 | 136篇 |
2006年 | 107篇 |
2005年 | 105篇 |
2004年 | 91篇 |
2003年 | 66篇 |
2002年 | 57篇 |
2001年 | 57篇 |
2000年 | 46篇 |
1999年 | 33篇 |
1998年 | 43篇 |
1997年 | 27篇 |
1996年 | 18篇 |
1995年 | 19篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1987年 | 4篇 |
1985年 | 16篇 |
1984年 | 23篇 |
1983年 | 20篇 |
1982年 | 18篇 |
1981年 | 9篇 |
1980年 | 22篇 |
1979年 | 8篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1976年 | 14篇 |
1975年 | 4篇 |
1974年 | 8篇 |
1973年 | 3篇 |
排序方式: 共有2850条查询结果,搜索用时 390 毫秒
81.
外观新颖性对消费者购买意愿的影响:自我建构与产品类型的调节效应 总被引:1,自引:0,他引:1
外观创新在市场竞争中的地位越来越突出,然而因此而导致的成败案例都很普遍。如何进行外观创新更受消费者欢迎,其内在机制是什么,我们却知之甚少。基于独特性需求理论、风险感知理论及自我建构理论,本文探讨了自我建构与外观新颖性对消费者购买意愿的交互作用、影响机制以及边界条件。通过3个实验,发现对于独立型自我建构的消费者而言,高外观新颖性能引发独特性需求从而提高购买意愿,而对于相依型自我建构而言,低外观新颖性则通过降低社会风险感知从而提高购买意愿;同时,本文也确定了产品类型对该机制的调节作用,具体来讲,对于实用品,所有消费者都对低外观新颖性产品具有更强的购买意愿,而对于享乐品,所有消费者都对高外观新颖性产品具有更强的购买意愿。 相似文献
82.
The visual acuity of the eyes varies outside the range of normal vision, requiring corrective lenses, but also within the normal range. This study investigated whether both types of variation relate to individual differences in face-identity matching, considering this applied task requires perception of detail. Across two experiments, face-matching accuracy correlated with variation in acuity when this fell outside the normal range of vision and was uncorrected with glasses or contact lenses. In contrast, variation in visual acuity within the normal range did not affect face-matching accuracy, whereas matching accuracy at a given level of acuity could vary substantially. These results indicate that visual acuity is only a problem for occupations performing face-identity matching when below-normal acuity is not diagnosed or adequately corrected. In turn, these findings suggest that variation in acuity within the normal range is not a contributing factor to individual differences in face matching accuracy. 相似文献
83.
84.
In two successive experiments using the divided visual field paradigm with vertical or horizontal division, two ambiguous figures, the Rubin’s vase-face or the Necker cube, were projected to the right and left or to the upper and lower visual hemifields of 108 healthy volunteers. Stimulation time was 120 s. The main hypotheses were (a) that different percepts of the same ambiguous figure may be simultaneously experienced in the two hemifields and (b) that the type (vertical vs. horizontal) of visual field division influences the reversal frequency and the temporal interdependence of the percepts.Results from the first experiment showed that the temporal interdependence of reversals was very low for both ambiguous figures, suggesting that during part of the stimulation time the subjects could experience different percepts of the same figure (e.g. a vase in the right and face profiles in the left visual hemifields). The second experiment showed that this perceptual dissociation occurred on average during one third of the stimulation time. In both experiments the type of visual field division did not influence either frequency or temporal interdependence of the reversals. When one single ambiguous figure was presented in the centre of the screen, the number of reversals was approximately the sum of the reversals observed with two figures presented simultaneously each in one hemifield. 相似文献
85.
This research study focused on the evaluation of an emulated in-vehicle Active Traffic and Demand Management (ATDM) system on Interstate 66 in Northern Virginia. Traditional ATDM systems rely on infrastructure-mounted variable message signs (VMS) to provide information (speed limits, lane availability, etc.) to the traveling public. By providing information about dynamic roadway conditions on an in-vehicle device, the ATDM may improve driving safety and performance by allowing drivers to remain consistently aware of forthcoming traffic conditions and roadway requirements; even when external signage is inaccessible. This study represents an initial investigation of an emulated in-vehicle ATDM to provide developers with design guidance and ensure that unintended consequences, such as distraction, do not undermine the potential benefits.Twenty younger and 20 older participants, accompanied by a member of the research team, experienced the following ATDM features on an in-vehicle device (IVD) mounted to the dashboard: (1) dynamic speed limits, (2) dynamic lane use/shoulder control, (3) High Occupancy Vehicle (HOV) restrictions, and (4) roadway information from variable message signs. The IVD was equipped with auditory and visual alerts notifying the driver when relevant visual information was updated. Research questions addressed distraction and driver behavior associated with use of the system. Qualitative and quantitative participant data was acquired from the instrumented vehicle, various questionnaires, and researcher observation.Several key findings were uncovered: (1) The IVD, as tested, did not warrant classification as a source of distraction according to the NHTSA guidelines; v2) There was a significant difference in eye-glance durations to the IVD when comparing the VMS alerts to both the speed limit and lane management alerts; and (3) The speed limit alert motivated participants to alter their speed (per survey results and participant speed data). 相似文献
86.
Gaze following plays a role in parent–infant communication and is a key mechanism by which infants acquire information about the world from social input. Gaze following in Deaf infants has been understudied. Twelve Deaf infants of Deaf parents (DoD) who had native exposure to American Sign Language (ASL) were gender‐matched and age‐matched (±7 days) to 60 spoken‐language hearing control infants. Results showed that the DoD infants had significantly higher gaze‐following scores than the hearing infants. We hypothesize that in the absence of auditory input, and with support from ASL‐fluent Deaf parents, infants become attuned to visual‐communicative signals from other people, which engenders increased gaze following. These findings underscore the need to revise the ‘deficit model’ of deafness. Deaf infants immersed in natural sign language from birth are better at understanding the signals and identifying the referential meaning of adults’ gaze behavior compared to hearing infants not exposed to sign language. Broader implications for theories of social‐cognitive development are discussed. A video abstract of this article can be viewed at https://youtu.be/QXCDK_CUmAI 相似文献
87.
Elizabeth A. Simpson Sarah E. Maylott Samantha G. Mitsven Guangyu Zeng Krisztina V. Jakobsen 《Developmental science》2020,23(2)
Humans detect faces efficiently from a young age. Face detection is critical for infants to identify and learn from relevant social stimuli in their environments. Faces with eye contact are an especially salient stimulus, and attention to the eyes in infancy is linked to the emergence of later sociality. Despite the importance of both of these early social skills—attending to faces and attending to the eyes—surprisingly little is known about how they interact. We used eye tracking to explore whether eye contact influences infants' face detection. Longitudinally, we examined 2‐, 4‐, and 6‐month‐olds' (N = 65) visual scanning of complex image arrays with human and animal faces varying in eye contact and head orientation. Across all ages, infants displayed superior detection of faces with eye contact; however, this effect varied as a function of species and head orientation. Infants were more attentive to human than animal faces and were more sensitive to eye and head orientation for human faces compared to animal faces. Unexpectedly, human faces with both averted heads and eyes received the most attention. This pattern may reflect the early emergence of gaze following—the ability to look where another individual looks—which begins to develop around this age. Infants may be especially interested in averted gaze faces, providing early scaffolding for joint attention. This study represents the first investigation to document infants' attention patterns to faces systematically varying in their attentional states. Together, these findings suggest that infants develop early, specialized functional conspecific face detection. 相似文献
88.
Research demonstrating that infants discriminate between small (e.g., 1 vs. 3 dots) and large numerosities (e.g., 8 vs. 16 dots) is central to theories concerning the origins of human numerical abilities. To date, there has been no quantitative meta‐analysis of the infant numerical competency data. Here, we quantitatively synthesize the evidential value of the available literature on infant numerosity discrimination using a meta‐analytic tool called p‐curve. In p‐curve the distribution of available p‐values is analyzed to determine whether the published literature examining particular hypotheses contains evidential value. p‐curves demonstrated evidential value for the hypotheses that infants can discriminate between both small and large unimodal and cross‐modal numerosities. However, the analyses also revealed that the published data on infants’ ability to discriminate between large numerosities is less robust and statistically powered than the data on their ability to discriminate small numerosities. We argue there is a need for adequately powered replication studies to enable stronger inferences in order to use infant data to ground theories concerning the ontogenesis of numerical cognition. 相似文献
89.
IntroductionLevel 2 driving automation features, such as adaptive cruise control (ACC) combined with lane centering, primarily communicate their operating statuses through the instrument cluster. It remains unclear how interface-specific training and display content influence the ability to understand Level 2 activity in production vehicles.MethodsEighty participants viewed videos recorded from the driver’s point of view in a variety of driving scenarios with Level 2 activity displayed in the instrument cluster of a 2017 Mercedes-Benz E-Class. Half viewed one of two instrument cluster layouts (simple or complex), and half received an orientation to the interface before the experiment. After each video, they were asked about the scenario they had just seen. We then examined what information in the displays participants used to identify Level 2 activity and the usability of the displays.ResultsTraining improved recognition accuracy of when lane centering was temporarily inactive and understanding of why it was inactive. Neither training nor display content affected the ability to recognize when ACC had adjusted the vehicle’s speed or detected a vehicle ahead, or when ACC initially did not detect a lead vehicle and understanding of why it had not detected it. Both factors influenced which sources of information participants used to determine Level 2 activity. Recognition accuracy of system activity improved when participants used valid sources of information. Training, but not display content, improved lane centering usability, but not ACC usability.DiscussionBasic training improves detection of notifications that potentially require further driver action, but not of those that display persistent status information. Training does not result in full understanding of all system notifications or functional limitations, which reinforces the need for intuitive, salient communication about system behavior and its limitations. 相似文献
90.
Crossing a road intersection, a driver must collect visual information from various locations. The allocation of visual attention, which allows this collection, mainly relies on top-down processes. This study focuses on three top-down factors which influence the collection of visual information: the value of visual information for the ongoing task, their bandwidth, and the familiarity with the environment. These factors are studied according to the priority rules at intersections (Give way, Stop or Priority), the expected traffic density (Lower or Higher) and the number of passages (First or Second passage). Fourteen participants were installed in an instrumented vehicle equipped with an eye-tracker. They drove during 1h45 along a 80-km long route, mainly on rural roads, which included 19 intersections. Visual attention was studied by means of the head and gaze horizontal eccentricity. Effects were found for each of the three factors, in agreement with Wickens’ theoretical framework and with previous studies, despite the important variability in the data due to the experimental situation. 相似文献