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121.
We investigated relationships among body size, the frequency of peak auditory sensitivity (best frequency) and acoustic conspicuousness (measured as target strength) to simulated bat echolocation calls in a range of tympanate moths (Lepidoptera: Noctuidae). Audiograms of Amphipyra pyramidea Linnaeus, Agrotis exclamationis Linnaeus, Omphaloscelis lunosa Haworth and Xestia xanthographa Denis and Schiffermüller are described for the first time. Best frequency was inversely related to forewing length, an index of body size. Models predict that target strength falls off rapidly once wavelength (1/frequency) exceeds some defined feature of target size (e.g. circumference for spheres). We investigated how target strength varies in relation to target size and emitted frequency for simple targets (paper discs) and for moths. Target strength fell rapidly when target radius/wavelength < 2 for paper discs of similar size to many noctuid moths. Target strength fell rapidly below wing‐length/wavelength ratios of 2 in relatively small (O. lunosa, wing‐length = 15.2 ± 0.4 mm, best frequency = 45 kHz) and large (N. pronuba, wing‐length = 24.6 ± 0.8 mm, best frequency = 15 kHz) noctuid species, and decreased rapidly at frequencies below 25 kHz in both species. These target strengths were used to predict the detection distance of the moths by bat sonar between 10 and 55 kHz. Predicted detection distances of both species were maximal for fictive call frequencies of 20 kHz, and were reduced at lower frequencies due to decreased target strength and at higher frequencies by excess atmospheric attenuation. Both relatively large and small noctuid moths are therefore strong acoustic targets to bats that echolocate at relatively low frequencies. Bats may emit allotonic calls at low frequency because the costs of reduced detection range are smaller than the benefits of reduced audibility to moths. Because best frequency scales with body size and maximum detection distance is not very sensitive to body size, noctuid moths in the size range examined do not necessarily have best frequencies that would match the call frequencies of bats that may detect the moths at greatest distance precisely. Hence, best frequency may be constrained in part by body size. 相似文献
122.
R. O’malley T. King C. S. Turner S. Tyler J. Benares M. Cummings P. Raines 《Biodiversity and Conservation》2006,15(1):43-56
Bats are the most diverse mammalian order in the Philippines and whilst many endemic and threatened species have been documented,
they are also probably the least well-known order. Negros Island (central Visayas, Philippines) represents one of the ten
highest-ranking sites globally for megachiropteran diversity, and is listed as a priority area for the establishment of protected
areas for megachiropteran conservation. It is also listed as a priority site for survey work. The current study undertook
mist-netting, roost and observation surveys of the bat fauna of Danjugan Island, off the west coast of Negros Occidental,
to inventory the bat species present and to provide baseline ecological information to identify key areas of conservation
concern. Eight species – five megachiropterans and three microchiropterans – were recorded over the course of the study, representing
over 10% of the total Philippine bat fauna. Four of the species are new records for the island, and three are IUCN Red Listed.
The results show that the island provides important cave- and tree-roosting areas for the local populations of several endemic
and globally endangered species and sub-species. Already designated with reserve status, and with an environmental education
programme established within the local communities, the island may be considered of national and global importance for bat
conservation. Recommendations are given for future management. 相似文献
123.
Chung Hsin Wu Philip H.-S. Jen 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2006,192(9):985-1002
When insectivorous bats such as Eptesicus fuscus emit ultrasonic signals and analyze the returning echoes to hunt insects, duration selectivity of auditory neurons plays an important role in echo recognition. The success of prey capture indicates that they can effectively encode progressively shortened echo duration throughout the hunting process. The present study examines the echo duration selectivity of neurons in the central nucleus of the bat inferior colliculus (IC) under stimulation conditions of single pulses and pulse–echo (P–E) pairs. This study also examines the role of gamma-aminobutyric acid (GABA)ergic inhibition in shaping echo duration selectivity of IC neurons. The data obtained show that the echo duration selectivity of IC neurons is sharper when determined with P–E pairs than with single pulses. Echo duration selectivity also sharpens with shortening of pulse duration and P–E gap. Bicuculline application decreases and GABA application increases echo duration selectivity of IC neurons. The degree of change in echo duration selectivity progressively increases with shortening of pulse duration and P–E gap during bicuculline application while the opposite is observed during the GABA application. These data indicate that the GABAergic inhibition contributes to sharpening of echo duration selectivity of IC neurons and facilitates echo recognition by bats throughout different phases of hunting. 相似文献
124.
2011 年6 月至2013 年7 月,利用雾网和抄网捕捉蝙蝠,采用直接计数、拍照等方法统计蝙蝠的数量,调查了河南省60 个洞穴中蝙蝠的种类、数量及分布,根据蝙蝠的外形及头骨特征鉴定种类,计3 科6 属17 种,其中易危(VU)物种3 种,近危(NT)和无危(LC)物种各7 种。马铁菊头蝠和菲菊头蝠为河南省广布种。依据洞穴的开发情况和人类入洞活动的频度等,评估洞穴的干扰程度,30 个洞穴属严重干扰,10 个洞穴属轻度干扰,20 个洞穴属自然状态。依据洞穴中蝙蝠的种类、数量及濒危程度,将洞穴的相对重要性划分为4 个级别,级别1 和多数级别2 的洞穴具有大的空间和复杂的洞穴系统,这些洞穴既是蝙蝠的繁殖地又是冬眠场所,其中栖息的蝙蝠种类多且数量大。对洞穴的总长度、最大宽度和最大高度进行了测量,比较4 个级别洞穴的测量数据,级别1 洞穴的总长度、最大宽度、最大高度的平均值明显大于其他级别。目前,多数洞穴未得到很好的保护,由于旅游开发等原因,洞栖蝙蝠正面临着严重的生存危机。 相似文献
125.
126.
P. H.-S. Jen X. M. Zhou 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1999,185(5):471-478
This study examines the effect of temporally patterned pulse trains on duration tuning characteristics of inferior collicular
neurons of the big brown bat, Eptesicus fuscus, under free-field stimulation conditions. Using a 50% difference between maximal and minimal responses as a criterion, the
duration tuning characteristics of inferior collicular neurons determined with pulse trains of different pulse durations are
described as band-pass, long-pass, short-pass, and all-pass. Each band-pass neuron discharged maximally to a specific pulse
duration that was at least 50% larger than the neuron's responses to a long- and a short-duration pulse. In contrast, each
long- or short-pass neuron discharged maximally to a range of long- or short-duration pulses that were at least 50% larger
than the minimal responses. The number of impulses of an all-pass neuron never differed by more than 50%. When pulse trains
were delivered at different pulse repetition rates, the number of short-pass and band-pass neurons progressively increased
with increasing pulse repetition rates. The slope of the duration tuning curves also became sharper when determined with pulse
trains at high pulse repetition rates. Possible mechanisms underlying these findings are discussed.
Accepted: 25 August 1999 相似文献
127.
Vanlalnghaka C Keny VL Satralkar MK Khare PV Pujari PD Joshi DS 《Chronobiology international》2005,22(5):793-800
Phase-response curves (PRCs) for the circadian rhythm of flight activity of the microchiropteran bat (Hipposideros speoris) were determined in a cave, employing discrete natural dawn and dusk twilight pulses. These PRCs are reported for the first time for any circadian system and they are unlike other PRCs constructed for nocturnal mammals. Dawn and dusk twilight pulses evoked advance and delay phase shifts, respectively. Advance phase shifts were followed by 3 to 4 advancing transients and a subsequent shortening of free-running period (τ); whereas, the delay phase shifts were instantaneous without any transients but with a subsequent lengthening of τ. 相似文献
128.
The study aimed to determine the influence of repeated natural dawn and dusk twilight pulses in entraining the circadian flight activity rhythm of the microchiropteran bat, Hipposideros speoris, free-running in constant darkness in a natural cave. The bats were exposed to repeated dawn or dusk twilight pulses at eight circadian phases. All bats exposed to dawn twilight pulses were entrained by advancing transients, and the stable entrainment was reached when the onset of activity occurred about 12 h before the lights-on of the pulses, irrespective of the initial phase at which the bats were exposed to twilight. All bats exposed to dusk twilight pulses, however, were entrained by delaying transients, and the stable entrainment was reached when the onset of activity occurred about 1.6 h after the lights-on of the pulses. The entrainment caused by dawn and dusk twilight pulses is discussed in the context of the postulated two photoreceptors: the short wavelength sensitive (S) photoreceptors mediating entrainment via dusk twilight, and the medium wavelength sensitive (M) photoreceptors mediating entrainment via dawn twilight. 相似文献
129.
130.
Identifying the informative genes has always been a major step in microarray data analysis. The complexity of various cancer datasets makes this issue still challenging. In this paper, a novel Bio-inspired Multi-objective algorithm is proposed for gene selection in microarray data classification specifically in the binary domain of feature selection. The presented method extends the traditional Bat Algorithm with refined formulations, effective multi-objective operators, and novel local search strategies employing social learning concepts in designing random walks. A hybrid model using the Fisher criterion is then applied to three widely-used microarray cancer datasets to explore significant biomarkers which reveal the effectiveness of the proposed method for genomic analysis. Experimental results unveil new combinations of informative biomarkers have association with other studies. 相似文献