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101.
This study aimed to reveal changes in spatial behaviour of common voles (Microtus arvalis) after alteration of their habitat by farming practices. Radio-collared common voles were tracked before and after mulching,
mowing, harvesting wheat, and ploughing in the flood plain of the river Unstrut in central Germany. Voles undisturbed by agricultural
practices were tracked on a mulchland, an abandoned pasture, and a cattle pasture. There was a large decrease in home-range
size after harvesting wheat (96%, P<0.001). Changes after mowing (–74%, P=0.06) were almost significant whereas changes after mulching were not (+14%, P=0.60). On the cattle pasture we found a decrease in home-range size (42%, P=0.03) possibly due to increased spatial activity of cattle in autumn. There was a positive correlation of home-range size
and vegetation height for plots with and without farming activity but no correlation with vegetation cover, population density,
and breeding. Radio-collared common voles did not show evasive movements and farming practices did not cause a shift of centres
of activity. Common voles clearly reacted to sudden changes in vegetation height, which may indicate an immediate response
to predation risk.
Electronic Publication 相似文献
102.
103.
核域是野生动物重点利用、含有更多居所、隐蔽场所及依赖性食物资源的区域。关于核域的确定和划分一直存在争议,且很难找到客观的并能准确展示动物生物学信息的数理统计方法。2006 年4 月,2006 年9 ~10月和2007 年1 ~4 月,我们共记录青海省都兰县沟里乡3 只藏狐的199 个活动位点,通过固定核空间(Fixed kernel)和调和平均值(Harmonic mean)模型,结合独立区域法的计算原理,估算藏狐的核域,并对两种估算方法进行比较分析,以确定更理想的核域数学模型。研究结果表明:(1)两种估算方法中核域面积均受到家域总面积的影响,固定核空间法的核域面积受家域总面积影响较大,而且变量系数不稳定; (2) 随着样本量的增加,固定核空间法估算的核域面积逐渐减小,而调和平均值法则增大,前者从数理统计上更好地描述了藏狐对家域资源的利用分布,后者更符合客观实际;(3)调和平均值法在划定家域边界时容易包括不属于家域范围的区域,而在估算核域时可以在一定程度上克服该缺陷;(4)调和平均值法能够真实地反应动物的活动中心,估算的核域中包含有更多的活动位点。因此,尽管在估算藏狐核域时固定核空间法有稳定的计算结果等优点,调和平均值法为更理想的核域估算模型。 相似文献
104.
A coarse-grained model of polypeptide chains confined in a slit formed by two parallel impenetrable surfaces was studied.
The chains were flexible heteropolymers (polypeptides) built of two kinds of united atoms—hydrophobic and hydrophilic. The
positions of the united atoms were restricted to the vertices of a [310] lattice. The force field consisted of a rigorous
excluded volume, a long-distance potential between a pair of amino-acid residues and a local preference for forming secondary
structure (helices). The properties of the chains were studied at a wide range of temperatures from good to bad solvent conditions.
Monte-Carlo simulations were carried out using the algorithm based on the chain’s local changes of conformation and employing
the Replica Exchange technique. The influence of the chain length, the distances between the confining surfaces, the temperature
and the force field on the dimension and the structure of chains were studied. It was shown that the presence of the confinement
chain complicates the process of the chain collapse to low-temperature structures. For some conditions, one can find a rapid
decrease of chain size and a second transition indicated by the rapid decrease of the total energy of the system.
Figure A scheme of a polypeptide chain built on a [310] lattice and confined to a slit formed by a pair of parallel impenetrable
surfaces
Proceedings of “Modeling Interactions in Biomolecules II,” Prague, September 5th–9th, 2005. 相似文献
105.
我们于2006年7月对分布于青藏高原东部若尔盖高寒湿地的7只高原林蛙(Rana kukunoris)进行了追踪研究。Monte-Carlo模拟表明:在研究期内高原林蛙的运动是随机的,还没有开始迁移。高原林蛙的平均运动距离为7.1m,雌雄运动距离没有差异。95%和50%Kernel家域分别为796.2m2±704.0m2和119.9m2±94.6m2,MCP家域为157.9m2±119.5m2。雌雄高原林蛙生境选择存在差异,雄性倾向于在洞穴较多的生境中运动和隐蔽,而雌性倾向于在草丛中运动和藏匿;早晨高原林蛙选择地面温度较高、相对湿度较大的微生境活动,雌雄活动点的空气温度、相对湿度和植被高度没有显著差异。追踪个体的微生境利用表明:高原林蛙和哺乳类洞穴具有很强的相关性。 相似文献
106.
Antoine Carof Virginie Marry Mathieu Salanne Jean-Pierre Hansen Pierre Turq 《Molecular simulation》2014,40(1-3):237-244
We investigate the possibility of describing by a continuous solvent model the dynamics of solutes confined down to the molecular scale. We derive a generalised Langevin equation (GLE) for the generic motion of a solute in an external potential using the Mori–Zwanzig formalism. We then compute the corresponding memory function from molecular simulations, in the case of cesium ions confined in the interlayer porosity of montmorillonite clays, with a very low water content (only six solvent molecules per ion). Previous attempts to describe the dynamics of cesium in this system by a simple Langevin equation were unsuccessful. The purpose of this work is not to carry out GLE simulations using the memory function from molecular simulations, but rather to analyse the separation of time scales between the confined ions and solvent. We show that such a separation is not achieved and discuss the relative contribution of the ion–surface, ion–solvent and ion–ion interactions to the dynamics. On the picosecond time scale, the ion oscillates in a surface-and-solvent cage, which relaxes on much longer time scales extending to several nanoseconds. The resulting overall dynamics resembles that of glasses or diffusion inside a solid by site-to-site hopping. 相似文献
107.
Guillemette Gauquelin-Koch Jean-Pierre Blanquie Michel Viso Genevive Florence Claude Milhaud Claude Gharib 《Journal of medical primatology》1996,25(6):387-396
Abstract: The purpose of this study was to characterize the hormonal responses to a restraining system in four adult male rhesus monkeys (Macaca mulatta) in preparation for a spaceflight project. After the monkeys were accustomed to food and water (Phase I), blood-volume-regulating hormones were measured during three phases: 10 days in a metabolic cage (Phase II), 16 days sitting in a restrained position in a specially designed metabolism chair (Phase III) and 10 days in metabolic cage (Phase IV). An increase of active renin (30%) and vasopressin (25%) was observed at the end of Phase III. A decrease of atrial natriuretic peptide (ANP), urodilatin, and sodium excretion occurred during the first days of Phase III. Catecholamines were unchanged. A dramatic increase (tenfold) in urinary excretion of growth hormone occurred during all of Phase III and at the beginning of Phase IV. These findings are similar to those found in man during isolation inactivity and during confinement stress. 相似文献
108.
109.
Steven C. Minta 《Oecologia》1993,96(3):402-409
I tested the following hypotheses of territorial polygyny on badgers (Taxidea taxus: Carnivora; Mustelidae): Competition among adult females for food should result in intrasexual territoriality, while male
competition for females should result in larger territories that encompass multiple female territories. The sagebrush-grassland
study area (Wyoming, USA) contained a depauperate terrestrial fauna with a dense badger population preying on high densities
of ground squirrels (Spermophilus armatus). Implant telemetry generated locations for analysis of home range and spatio-temporal interaction. During the summer breeding
season males doubled movement rates and nearly tripled home range areas to overlap those of females. Before and after the
breeding season, males reduced their home ranges to sizes nearer those of stable female ranges (
=2.82 km2). Unexpectedly, home range overlap between males and females was no different than intrasexual overlap. However, analysis
of spatio-temporal interaction revealed that females spatially avoided one another, while males were spatially and temporally
attacted to one another, similar to that of male-female interactions. Presumably, olfactory mechanisms allow resource tracking
and lagged communication. Male-male territoriality was not viable, most likely because the high density of badgers, combined
with the severely male-biased sex ratio (1.75:1), effectively increased intruder pressure — as a resource, receptive females
were too mobile and spatially unpredictable within their home ranges. Consequently, males monitored and searched widely for
relatively scarce females during the breeding season with the effect of attracting each other. Male mobility, home range size,
and possibly aggression increased with age, suggesting age-related breeding tactics, although dominance could only be surmised.
This and other studies suggest how the spatial, temporal, and dominance components of carnivore resource partitioning and
sociality will be understood better by unraveling the interplay of olfactory processes, attributes of disparate resources
(e.g., food vs. females), seasonality, and population density and age-sex structure. 相似文献
110.
Home range and habitat use by the sable<Emphasis Type="Italic"> Martes zibellina brachyura</Emphasis> in a Japanese cool-temperate mixed forest 总被引:1,自引:0,他引:1
Home range and habitat use of the sable Martes zibellina brachyura were studied in a cool-temperate mixed forest in northernmost Japan. In both sexes, some sables showed a wide range of migration without establishing home ranges and the others had home ranges of 0.50–1.78 km2 (mean: 1.12±SD 0.495 km2, n =6) which were not significantly correlated with body weight or age. The analysis of canine tooth annuli revealed that the maximum age was 5.5 years. The home ranges of some sables overlapped so extensively that the home ranges and even the core areas did not appear exclusive to other sables. We determined resting sites and foraging routes in snow in winter. Comparison of vegetation at the resting sites and foraging routes with habitat availability suggested that the sables preferred resting in dense-tree forests with many tree species and debris probably in order to avoid predators (red foxes) and strong wind and foraging in forests of climax succession which are usually rich in their prey such as voles and mice. 相似文献