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1.
Abstract: Studies of space use and habitat selection of endangered species are useful for identifying factors that influence fitness of individuals and viability of populations. However, there is a lack of published information regarding these behaviors for the federally threatened Louisiana black bear (Ursus americanus luteolus). We documented space use and habitat selection for 28 female black bears in 2 subpopulations of the Tensas River Basin population in northeast Louisiana, USA. The Tensas subpopulation inhabits a relatively large (>300-km2) contiguous area of bottomland hardwood forest, whereas the Deltic subpopulation exists mainly in 2 small (<7-km2) forested patches surrounded by an agricultural matrix. Females on Deltic maintained smaller seasonal and annual home ranges than females on Tensas (all P < 0.04), except for females with cubs during spring. On Tensas, females with cubs maintained smaller home ranges than females without cubs during spring (P = 0.01), but we did not detect this difference on Deltic or in other seasons. Females on Tensas and Deltic exhibited differences in habitat selection when establishing home ranges and within home ranges (P < 0.001). Deltic females selected mature bottomland hardwood forests and avoided agricultural habitats at both spatial scales. Tensas females selected a mixture of swamps, mature and regenerating forests, and exhibited variation in selection across scale, season, and reproductive status. We suggest that differences in space use and habitat selection between Tensas and Deltic are at least partially due to habitat differences at the landscape (i.e., amount of forested habitat) and patch (i.e., food availability) scales. Our results contribute to the understanding of factors that influence space use and habitat selection by black bears and provide specific information on habitat types selected by Louisiana black bears to agencies involved in habitat protection and restoration for this threatened subspecies. 相似文献
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The biosynthesis of sedoheptulose in the Sedum plant was studied in order to develop procedures for synthesizing C14-labeled sedoheptulose in optimal yield.The rate of formation of C14-labeled sedoheptulose as well as its relationship to that of the other C14-labeled compounds, especially sucrose, glucose, and fructose, was studied. The rate of accumulation of free sedoheptulose in Sedum spectabile varied considerably with the age of the plants, the conditions under which the plants were kept before the experiments (atmospheric conditions, light and dark treatments), and the medium (water or nutrient solution) in which the plants were kept during the photosynthesis.Very small amounts of C14-labeled sedoheptulose formed during the first 24 hr. of photosynthesis in C14O2 in both mature and young leaves. Free sedoheptulose accumulates and is depleted much more slowly than are sucrose, glucose, and fructose. Starved plants deprived of their reservoir of free hexoses by respiration still contained remarkably large amounts of free sedoheptulose. In C14O2 they were always found to accumulate very little free radioactive sedoheptulose until the reservoirs of hexoses were restored. It is concluded that the unique sedoheptulose accumulation in Sedum is largely due to the relative inactivity of the required kinase. 相似文献
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SYNOPSIS. The beginnings of professional natural history inSeattle date from 1879. In this year a group of young men whowere completely untrained in the sciences formed the Young Naturalists'Society. The society quickly grew to eventually become a majorinstitution for natural history investigations in the PugetSound area at the end of the nineteenth century. The activitiesof the Young Naturalists included collecting a large and impressivecabinet, exchanging specimens with naturalists throughout theUnited States, organizing expeditions for marine investigations,and providing educational opportunities for the public throughlectures, public exhibits, newspaper reports, and summer Chautauqua.As the society became more professional in its work, it developedstrong ties to the University of Washington. In fact, by themid-1890s it was difficult to separate the natural history worksponsored by the University from the studies under the aegisof the Young Naturalists. Eventually the society disbanded andbecame absorbed by the various natural science departments ofthe University and by the Washington State Museum. The importanceof the Young Naturalists' was through its critical role in providingthe foundation for the development of a professional naturalhistory community in Seattle. 相似文献
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JANET BENSON 《American anthropologist》2006,108(3):619-620
The New Immigration: An Interdisciplinary Reader. Marcelo M. Suarez-Orozco, Carola Suarez-Orozco, and Desiree Baolian Quin, eds. New York: Routledge, 2005. 366 pp. 相似文献
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Seventeen light-trap samples were taken over a 20 month period at Yuccabine Creek, an upland rainforest stream in north-eastern Queensland. Seventy-eight species of Trichoptera were recorded from a total catch of 6431 individuals. The fauna was dominated by the Hydroptilidae (25 species and 5131 individuals) and, though composed primarily of Torresian genera, some Bassian elements were recorded. A seasonal pattern of change of abundance was observed with the majority of tax a exhibiting maxima between December and January (summer) and minima between July and September (winter). 相似文献
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