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111.
A. Schmidt J. Engelage H.-J. Bischof 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1999,185(1):69-79
Responses of neurons of the optic tectum, the prominent, highly laminated mesencephalic station of the tectofugal visual
pathway in birds, to computer-generated and other visual stimuli were examined in zebra finches. Our study shows that the
contralateral retina projects to the tectum in topographic order. The representation of the visual field is tilted against
the horizon by 22°. The representation of the contralateral hemifield extends to the ipsilateral side by 15°. Most neurons
have receptive fields with excitatory centres of different shapes and inhibitory surround. A new type of neuronal receptive
field is described which has an excitatory centre and a surround which is movement sensitive and preferably excited by very
small spots. The first type of neurons is mostly located in upper tectal layers, the latter only in deeper layers. Excitatory
centre sizes increase with depth, and there is a tendency of smaller receptive fields in the foveal region. The representation
of the frontal visual field does not show specializations which could be expected if it were used for fixation of grain during
pecking. Our results are in accordance with previous behavioural experiments.
Accepted: 30 April 1999 相似文献
112.
Sweetened ethanol drinking during social isolation: enhanced intake,resistance to genetic heterogeneity and the emergence of a distinctive drinking pattern in adolescent mice
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With its ease of availability during adolescence, sweetened ethanol (‘alcopops’) is consumed within many contexts. We asked here whether genetically based differences in social motivation are associated with how the adolescent social environment impacts voluntary ethanol intake. Mice with previously described differences in sociability (BALB/cJ, C57BL/6J, FVB/NJ and MSM/MsJ strains) were weaned into isolation or same‐sex pairs (postnatal day, PD, 21), and then given continuous access to two fluids on PDs 34–45: one containing water and the other containing an ascending series of saccharin‐sweetened ethanol (3–6–10%). Prior to the introduction of ethanol (PDs 30–33), increased water and food intake was detected in some of the isolation‐reared groups, and controls indicated that isolated mice also consumed more ‘saccharin‐only’ solution. Voluntary drinking of ‘ethanol‐only’ was also higher in a subset of the isolated groups on PDs 46–49. However, sweetened ethanol intake was increased in all isolated strain × sex combinations irrespective of genotype. Surprisingly, blood ethanol concentration (BEC) was not different between these isolate and socially housed groups 4 h into the dark phase. Using lickometer‐based measures of intake in FVB mice, we identified that a predominance of increased drinking during isolation transpired outside of the typical circadian consumption peak, occurring ≈8.5 h into the dark phase, with an associated difference in BEC. These findings collectively indicate that isolate housing leads to increased consumption of rewarding substances in adolescent mice independent of their genotype, and that for ethanol this may be because of when individuals drink during the circadian cycle. 相似文献
113.
异色瓢虫视觉系统中5-HT阳性神经元的分布 总被引:1,自引:0,他引:1
本文运用树脂石蜡(Colophony-Paraffin,CP;专利号:ZL98125709.7)组织包埋切片技术,结合免疫组织化学链酶菌抗生物素蛋白一过氧化物酶(Streptavidin-Peroxidase,SP)双染法,对异色瓢虫视觉系统中5-羟色胺(5-HT)能神经元的分布进行了初步研究。结果显示,异色瓢虫视觉系统的结构及5-HT免疫反应系统相对比较特殊。5-HT阳性神经元胞体数目较少,染色显著,并聚集成群。根据胞体定位、细胞形态及轴突走向,可大体分为5群,其中包括1群呈弱反应的光感细胞。5-HT阳性膨大纤维支配所有的视神经纤维网,并呈柱状或分层排列模式。结果表明5-HT作为经典的神经递质在昆虫的视觉信息处理过程中可能发挥重要的调节作用,且主要以远距离的广域神经调节模式为主,并在特定区域和GABA有伴随现象。此外,昆虫视觉系统中5-HT的含量还可能与其明暗适应的生理调节方式具有相关性[动物学报51(5):912—918,2005]。 相似文献
114.
Group members present physical and physiological differences according to their age, sex or social status, which could generate
motivation differences among individuals during travel. In spite of these divergences of interest among individuals, the group
succeeds more often than not in making a collective decision about departure time and which direction to take. To reach a
consensus decision, animals should exchange information relating to characteristics of group movement through different communication
channels. The main purpose of this study is to understand the function of behaviour patterns displayed during movements of
white-faced capuchins (Cebus capucinus). We designed experiments in which we provoked collective movements involving a binary choice. During experiments, a video
camera recorded the behaviour of each capuchin, which enabled us to determine which individuals displayed a behavioural pattern
during travel and how this behaviour influenced the other group members. We found that looking backwards seemed to permit
the recruitment of group mates during collective movement. This behaviour also seemed to allow the quantification of the number
of followers, since the emitter modified its locomotion speed according to this number. In this preliminary study, we showed
that visual behaviour was used to recruit and monitor group mates during collective movements and provided information on
mechanisms involved in maintaining cohesion and coordination among group members during travel. 相似文献
115.
116.
In most species of small mammals, males are exposed to higher levels of risk than females because they compete for mates,
travel greater distances to find and procure mates, and/or defend a territory. This suggests that males and females might
have different responses to risky situations, such as the presence of a predator. We tested responses to a visual predator
cue (an owl silhouette) in male and female golden hamsters (Mesocricetus auratus). In a laboratory arena, there was no significant sex difference in the latency to enter the burrow or time spent in the
burrow immediately after exposure to the owl silhouette. Males, however, were less likely to be active during the 3-min period
following the animal’s exposure to the silhouette, indicating that male golden hamsters are more wary after exposure to an
aerial predator cue than females. Most studies of responses to predators or predator cues have not considered sex differences,
but our results show that males and females may have quite different responses to predator cues. Further work should be done
to characterize and quantify sex differences in response to predators or predator cues. 相似文献
117.
The fragmentation of landscapes produces habitat gaps where the distance between visual landmarks may exceed the perceptual
range of a species and impose navigational constraints. We estimated the visual perceptual range of the Australian sleepy
lizard, Tiliqua rugosa, by releasing individuals in the centre of a cleared arena in high temperature conditions, with a 0.5-m-high bush placed
either 10, 20 or 30 m from the release site. Lizards were more likely to locate those bushes and shelter under them when they
were closer, and no lizards found a bush at 30 m. In addition, lizards were less likely to move from the release point when
bushes were at 30 m than when they were at the two closer distances. These data suggest that for sleepy lizards the perceptual
range for a 0.5-m-high bush is about 20 m. In the uncleared chenopod shrub-land where these lizards live, suitable shelter
bushes are an average of 10.5 m from any point in their home range, well within their perceptual range. 相似文献
118.
In this paper we present an improved model for line and edge detection in cortical area V1. This model is based on responses of simple and complex cells, and it is multi-scale with no free parameters. We illustrate the use of the multi-scale line/edge representation in different processes: visual reconstruction or brightness perception, automatic scale selection and object segregation. A two-level object categorization scenario is tested in which pre-categorization is based on coarse scales only and final categorization on coarse plus fine scales. We also present a multi-scale object and face recognition model. Processing schemes are discussed in the framework of a complete cortical architecture. The fact that brightness perception and object recognition may be based on the same symbolic image representation is an indication that the entire (visual) cortex is involved in consciousness. 相似文献
119.
120.
Frederike Diana Hanke Guido Dehnhardt 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2009,195(7):643-650
In this study, we measured aerial visual acuity in harbor seals. As a first approach to the hypothesis that harbor seals can
obtain acute aerial visual acuity mediated by the interaction of the vertical slit-shaped pupil and the corneal flattening
although refractive measurements had revealed aerial myopia, visual acuity was tested as a function of luminance and pupil
dilation. We analyzed aerial visual acuity (minimal resolvable stripe width) in three harbor seals in a two-alternative-forced-choice
discrimination experiment. Our results further support the hypothesis that harbor seals possess an aerial visual acuity comparable
to the acuity in clear waters if the vertical slit pupil does not exceed the zone of corneal flattening in bright light. When
the pupil dilates with decreasing luminance, visual acuity decreases which might be due to deflected light from the stronger
curved peripheral cornea. 相似文献