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排序方式: 共有239条查询结果,搜索用时 312 毫秒
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Marguerite Hureaux Sarah Guterman Bérénice Hervé Marianne Till Sylvie Jaillard Sylvie Redon Myléne Valduga Charles Coutton Chantal Missirian Fabienne Prieur Brigitte Simon-Bouy Claire Beneteau Paul Kuentz Caroline Rooryck Nicolas Gruchy Nathalie Marle Morgane Plutino Lucie Tosca Celine Dupont Jacques Puechberty Caroline Schluth-Bolard Laurent Salomon Damien Sanlaville Valérie Malan François Vialard 《黑龙江环境通报》2019,39(6):464-470
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Summary. Most dung beetles colonize the faeces of several vertebrate species without much discrimination, and are thus often considered
as polyphagous. Recent studies have provided evidence for clear feeding preferences in scarab beetles colonizing dung of herbivore
species, but little is known about these insects’ abilities to discriminate among odours from faeces of various herbivores.
In this study, trophic preferences were examined using blocks of pitfall traps baited with dung from four different herbivore
species, i.e., sheep, cattle, horse, and red deer, in a mountainous area of south-central France. 4941 coprophagous scarabs,
belonging to 27 species, were captured. Beetles were more attracted to dung of sheep (2257 individuals) than that of cattle
(1294 individuals), followed by deer dung (768 individuals) and horse dung (622 individuals). Eleven of the 27 beetle species
collected had significant feeding preferences for one of the four dung types. For each insect species, trophic habits did
not vary between the two different sites of trapping, an open pasture and a wooded habitat. In laboratory olfactometer bioassays,
scarab beetles orientated preferentially towards the dung volatiles from the dung type they preferred in the field. Trypocopris pyrenaeus, Anoplotrupes stercorosus, and Aphodius rufipes were more attracted to volatile compounds from sheep dung, Onthophagus fracticornis significantly preferred horse dung volatiles, and Aphodius haemorrhoidalis responded positively to deer dung odours. The role of dung olfactory cues in the process of resource selection by dung beetles
is discussed. 相似文献
158.
Laurent Guibaud 《黑龙江环境通报》2009,29(4):420-433
More than 20 years after its introduction, magnetic resonance imaging (MRI) is now considered a useful complementary tool in the imaging work-up of fetal brain structural anomalies, but its real contribution in neuro-fetal imaging is still controversial. Our purpose is to present an overview of the most valuable indications of fetal cerebral MRI in current practice as guided by dedicated ultrasound analysis. On the basis of a review of the literature and our personal experience, we underline herein the real complementarities between these two techniques in different clinical or imaging settings and show how MRI adds significant information compared with ultrasound, especially in the late second and third trimesters. We assess the interest of using MRI from a technical point of view (complete and extensive anatomical analysis, analysis of developmental and pathological processes) and from a practical point of view in different imaging and clinical settings. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
159.
We examine the role of food resources on split sex ratios in Formica exsecta. Models of resource-based sex allocation predict that greater resources will cause an increase in the production of reproductive females (gynes) and an increase in overall size of offspring. We experimentally increased food resources for a subset of colonies in a polygynous population with a very male-biased sex ratio. This increase in food availability caused colonies that were male specialists the prior year to switch to female production. Overall, a significantly greater proportion of food-supplemented colonies produced gynes, compared to control colonies. Moreover, food-supplemented colonies produced significantly larger workers and males (but not gynes), compared to those produced by control colonies. There was, however, no significant difference in the numerical productivity of food-supplemented and control colonies. We also measured the natural association between colony sex specialization and proximity to conifers, which typically harbor honeydew-bearing aphids (an important natural food source). In line with the view that resources play an important role for determining sex ratios in social insects, we found that female-producing colonies were significantly closer to conifers than were male-producing colonies. 相似文献
160.
Laurent Keller Liselotte Sundström Michel Chapuisat 《Behavioral ecology and sociobiology》1997,41(1):11-15
The relative number of workers and female sexuals fathered by two males mated with a queen were directly assessed using microsatellite
and allozyme markers in field colonies of the ants Formica exsecta and F. truncorum. In both species one of the two males consistently fathered more offspring than the other. There was, however, no evidence
that one male might be particularly successful in fathering a disproportionally high proportion of female sexuals relative
to the proportion of workers. Moreover, in F. exsecta, the proportions of worker pupae and worker adults fathered by each male did not differ significantly between cohorts. The
most likely explanation for this pattern is that females store different amounts of sperm from the two males they mated with.
Received: 10 January 1997 / Accepted after revision: 22 March 1997 相似文献