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Age at first breeding and fitness in goshawk Accipiter gentilis 总被引:1,自引:0,他引:1
OLIVER KRÜGER 《The Journal of animal ecology》2005,74(2):266-273
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回顾2010—2019年国土空间规划背景下的风景园林发展动态,梳理相关的政策法规和研究文献,使用文献计量分析与内容分析法,并结合科学计量工具CiteSpace进行科学图谱分析。根据关键词出现频次的可视化结果,将国土空间规划视角下的风景园林发展结合同期的相关政策与技术标准进行整体分析。此外,提炼国土空间规划视角下的3个风景园林相关的发展热点,包括国土空间规划中的生态建设、国家公园体制以及实践与管理,结合最新的国土空间规划相关政策与技术标准进行细化论述。最后提出未来发展趋势的展望,以期为探索国土空间规划提供风景园林视角上的贡献。 相似文献
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Christopher A. M. Hammond Michael S. Mitchell Gael N. Bissell 《The Journal of wildlife management》2012,76(3):645-651
Structure and distribution of animal territories are driven by a variety of environmental and demographic factors. A peninsular population of common loons (Gavia immer) nests on lakes in northwestern Montana, but does not occupy all apparently suitable breeding territories, suggesting unexplained limitations on population growth. To evaluate territorial dynamics of breeding loons in Montana, we created and tested occupancy models that evaluated the hypothesized effects of disturbance, habitat, and intraspecific relationships on territory occupancy by common loons in Montana from 2003 to 2007. Model-averaged results indicated that the abundance of feeding lakes within 10 km (i.e., forage quality) and the number of territorial pairs within 10 km (i.e., density of loons) were equally supported and related to probabilities of occupancy. We found substantial support that the population was in a state of equilibrium, with the numbers of occupied territories stable in time, but not space. We also found that density of territorial pairs was related to the likelihood that an existing territory would be abandoned, but did not influence the establishment of new territories, suggesting the presence of territorial pairs could be a stronger indicator of territory quality to loons than physical lake characteristics. Our index of human disturbance was not well-supported compared to other factors. Our results suggest management for stable or growing loon populations could be achieved using long-term monitoring and protection of occupied territorial lakes and nearby feeding lakes, because these factors most influenced the probability of occupancy of surrounding lakes. © 2011 The Wildlife Society. 相似文献
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JAMES J. GILROY GUY Q. A. ANDERSON PHILIP V. GRICE JULIET A. VICKERY & WILLIAM J. SUTHERLAND 《Ibis》2010,152(1):90-104
Declines in habitat quality through the breeding season within a bird's home-range can limit overall productivity. In environments where multiple breeding opportunities arise during the course of a season, these effects can be buffered by a shift to different breeding sites or habitats. We studied the distribution and habitat associations of a crop-nesting farmland bird, the Yellow Wagtail Motacilla flava , across an arable-dominated farming region in eastern England using both field-scale territory mapping and large-scale transect surveys. Surveys were repeated at monthly intervals to measure changes in both distribution and habitat use during the course of the season. The distribution of breeding birds changed markedly at both regional and field-scales, coinciding with a shift in crop preference. Initially, most territorial birds were recorded in autumn-sown cereal fields, but this crop was subsequently abandoned in favour of potato crops, which were more patchily distributed. Other habitat features influencing Yellow Wagtail distribution included local crop diversity, hedgerow presence and soil type, with organic soils supporting higher abundance than alluvial clays or silts. The mid-season switch in habitat associations might allow individuals to maximize the number of breeding attempts made in a single year by using multiple habitats sequentially. The use of multiple habitats could influence population regulation by buffering the effects of local within-season declines in habitat suitability. Seasonal habitat switching may be more prevalent than is currently recognized in seasonal environments. 相似文献
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Caroline Bilhete James W.A. Grant 《Ethology : formerly Zeitschrift fur Tierpsychologie》2016,122(2):151-157
An increase in habitat complexity is thought to decrease visibility and the territory size of visually oriented animals. Hence, the addition of physical structure has been viewed as a useful restoration technique to increase the density of territorial species, particularly in stream fishes. However, a decrease in territory size may have a negative effect on the fitness of individual organisms. We attempted to quantify some of the positive and negative effects of increasing habitat structure on the behaviour and growth rate of wild young‐of‐the‐year (YOY) Atlantic salmon. Fish were exposed to one of two habitat treatments in mesh enclosures in Catamaran Brook, New Brunswick: a gravel substrate (low complexity) or a gravel substrate with boulders added (high complexity). Wild‐caught individuals were tagged, weighed and measured before being stocked at densities of 1·m?2 for 7‐d trials. While fish from high‐complexity treatments benefited from lower rates of aggression, they also had lower foraging rates and smaller territories compared to those in low‐complexity treatments. Specific growth rate, however, did not differ significantly between treatments. While the addition of structure to a habitat may be beneficial at the population level in terms of an increase in population density, our results suggested that individual fish may pay some short‐term costs in these environments. Further research is needed to evaluate the longer term costs and benefits of adding structure to improve the habitat quality for stream salmonids. 相似文献