全文获取类型
收费全文 | 575篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
587篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2015年 | 4篇 |
2014年 | 24篇 |
2013年 | 23篇 |
2012年 | 11篇 |
2011年 | 23篇 |
2010年 | 12篇 |
2009年 | 25篇 |
2008年 | 35篇 |
2007年 | 22篇 |
2006年 | 20篇 |
2005年 | 26篇 |
2004年 | 27篇 |
2003年 | 27篇 |
2002年 | 9篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 10篇 |
1998年 | 9篇 |
1997年 | 9篇 |
1996年 | 12篇 |
1995年 | 12篇 |
1994年 | 15篇 |
1993年 | 12篇 |
1992年 | 15篇 |
1991年 | 15篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1974年 | 4篇 |
1973年 | 6篇 |
1972年 | 8篇 |
1971年 | 10篇 |
1969年 | 2篇 |
排序方式: 共有587条查询结果,搜索用时 15 毫秒
81.
Phalloidin‐stained whole mounts of acoel turbellarians show brightly fluorescing club‐shaped structures distributed over the epidermis and concentrated especially at the anterior and posterior tips of the body. By correlating electron micrographic images and fluorescence images of Convoluta pulchra, these structures can be seen to be sensory receptors with a central cilium surrounded by a collar of microvilli. The other candidate for showing fluorescence in the epidermis, namely gland necks, can be ruled out since their distribution is too dense to resemble the distribution of the fluorescent structures seen here. The collared sensory receptors were inserted between epidermal cells, and each bore a central cilium surrounded by a collar of 6–18 microvilli and an additional centrally positioned 2–7 microvilli of which 2 or 3 were associated with a modified rootlet called the swallow’s nest. Confocal scanning laser microscopy resolved the core of actin filaments within the microvilli of the collar and their rootlet‐like connections to the base of the sensory cell. Such receptors could also be identified by fluorescence microscopy in several other species of acoel turbellarians. 相似文献
82.
Yasuo Uehara 《Cell and tissue research》1973,136(4):511-520
83.
84.
P. Roessingh K. H. Hora J. J. A. van Loon S. B. J. Menken 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1999,184(1):119-126
The cellular localisation of the sensitivity to two host-plant specific larval phagostimulants was determined in Yponomeuta evonymellus and in inter-specific hybrids of Y. cagnagellus and Y. padellus. The combined results of cross-adaptation experiments, analysis of mixture responses and inter-spike interval distributions
indicated that the sensitivity for sorbitol and dulcitol is localised in the same cell in the investigated species. This result
suggests that during the evolution of the genus the main alteration in the mechanism of sugar-alcohol detection occurred at
the level of the receptor proteins. Relatively simple modification of this kind can, however, have large effects, since larvae
with modified receptor proteins will directly respond to the new stimulus while all central processing and resulting behaviour
can remain unmodified.
Accepted: 7 October 1998 相似文献
85.
I. Iscla P. D. Arini L. Szczupak 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1999,184(2):233-241
We studied a specific sensory-motor pathway in the isolated leech ganglia. Pressure-sensitive mechanosensory neurons were
stimulated with trains of action potentials at 5–20 Hz while recording the responses of the annulus erector motorneurons that
control annuli erection. The response of the annulus erector neurons was a succession of excitatory postsynaptic potentials
followed by inhibitory postsynaptic potentials. The excitatory postsynaptic potentials had a brief time-course while the inhibitory
postsynaptic potentials had a prolonged time-course that enabled their temporal summation. Thus, the net effect of pressure-sensitive
neuron stimulation on the annulus erector neurons was inhibitory. Both phases of the response were mediated by chemical transmission;
the excitatory postsynaptic potentials were transmitted via a monosynaptic pathway, and the inhibitory postsynaptic potentials
via a polysynaptic one. The pattern of expression of this dual response depended on the field of innervation of the sensory
neuron and it was under the influence of cell 151, a non-spiking interneuron, that could regulate the expression of the hyperpolarization.
The interaction between pressure-sensitive neurons and annulus erector neuron reveals how sensory specificity, connectivity
pattern and regulatory elements interplay in a specific sensory-motor network.
Accepted: 6 November 1998 相似文献
86.
Achraf Ammar Omar Boukhris Hsen Hsouna Imen Ben Dhia Khaled Trabelsi Tariq Ali Gujar Cain C.T Clark Hamdi Chtourou Tarak Driss Anita Hoekelmann 《Biology of sport / Institute of Sport》2021,38(4):683
Although napping is commonly used as a strategy to improve numerous physical and cognitive performances, the efficacy of this strategy for improving postural balance has not yet been elucidated. Thus, the aim of this study was to conduct a comprehensive examination of the effect of a 60 min nap opportunity (N60) on different components of postural control. Ten highly active individuals (age = 27 ± 3.5 y, height = 1.75 ± 0.52 m, weight = 66.02 ± 8.63 kg) performed, in a randomized order, two afternoon test sessions following no nap (NN) and N60. Postural balance was assessed using the sensory organisation test (SOT), the unilateral stance test (UST), and the limits of Stability Test performed on NeuroCom® Smart Balance Master. The subjective rating of sleepiness before and after the nap conditions was also assessed. Compared to NN, N60 improved the composite balance score (p < 0.05, ES = 0.75, Δ = 5.3%) and the average and maximum percentage balance in the most challenging postural conditions of the SOT (p < 0.05 for SOT-4 and 5 and p < 0.0005 for SOT-6; ES range between 0.58 and 1.1). This enhanced postural balance in N60 was accompanied with improved visual (p < 0.05; ES = 0.93; Δ = 8.9%) and vestibular (p < 0.05; ES = 0.81; Δ = 10.5%) ratios and a reduced level of sleepiness perception (p < 0.001, ES = 0.87). However, no significant differences were found in any of the UST and LOS components’ scores (p > 0.05). Overall, a 60 min post lunch nap opportunity may be viable for improving static balance, although further work, involving larger samples and more complex motor activities, is warranted. 相似文献
87.
88.
Ramachandra M. Bhaskara C. M. Brijesh Saveer Ahmed Renee M. Borges 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2009,195(4):409-417
The perception of ultraviolet (UV) light by spiders has so far been only demonstrated in salticids. Crab spiders (Thomisidae)
hunt mostly on flowers and need to find appropriate hunting sites. Previous studies have shown that some crab spiders that
reflect UV light use UV contrast to enhance prey capture. The high UV contrast can be obtained either by modulation of body
colouration or active selection of appropriate backgrounds for foraging. We show that crab spiders (Thomisus sp.) hunting on Spathiphyllum plants use chromatic contrast, especially UV contrast, to make themselves attractive to hymenopteran prey. Apart from that,
they are able to achieve high UV contrast by active selection of non-UV reflecting surfaces when given a choice of UV-reflecting
and non-UV reflecting surfaces in the absence of odour cues. Honeybees (Apis cerana) approached Spathiphyllum plants bearing crab spiders on which the spiders were high UV-contrast targets with greater frequency than those plants on
which the UV contrast of the spiders was low. Thus, crab spiders can perceive UV and may use it to choose appropriate backgrounds
to enhance prey capture, by exploiting the attraction of prey such as honeybees to UV. 相似文献
89.
90.
Yuko Arie Masumi Iketani Ken Takamatsu Yoshio Goshima 《Biochemical and biophysical research communications》2009,379(1):11-3034
Intracellular calcium ions (Ca2+) have an essential role in the regulation of neurite outgrowth, but how outgrowth is controlled remains largely unknown. In this study, we examined how the mechanisms of neurite outgrowth change during development in chick and mouse dorsal root ganglion neurons. 2APB, a potent inhibitor of inositol 1,4,5-trisphosphate (IP3) receptors (IP3R), inhibited neurite outgrowth at early developmental stages, but not at later stages. In contrast, pharmacological inhibition with Ni2+, Cd2+, or dantrolene revealed that ryanodine receptor (RyR)-mediated Ca2+-induced Ca2+ release (CICR) was involved in neurite outgrowth at later stage, but not at early stages. The distribution of IP3R and RyR in growth cones also changed during development. Furthermore, pharmacological inhibition of the Ca2+-calmodulin-dependent phosphatase calcineurin with FK506 reduced neurite outgrowth only at early stages. These data suggest that the calcium signaling that regulates neurite outgrowth may change during development from an IP3R-mediated pathway to a RyR-mediated pathway. 相似文献