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Klaus Mittenzwei Gudbrand Lien Wendy Fjellstad Eva Øvren Wenche Dramstad 《Journal of environmental management》2010,91(4):861-868
Protected Landscapes (PLs) are increasingly used in Norway to conserve cultural (human modified) landscapes. In many cases the maintenance of agricultural activities in PLs is required to preserve landscape character. Whilst research exists on land conservation policies in general, the particular effects of PL on management and adjustment of the farms involved have not received attention in the literature. We present results from a questionnaire sent to owners of agricultural land within PLs in Norway. Whilst landowners were divided upon the effects of PLs on farm management, the economic situation of the farm was little affected. Furthermore, changes in farm management after the establishment of a PL did not seem to have been driven by the establishment of the PLs per se. Most importantly, farm management changes were related to potential options to develop the farm and its land. A statistical model showed that PL-farms did not differ significantly from farms outside PL in the development of their land use or animal husbandry. Our findings thus indicate that the establishment of PL played a minor role as a driving force of changes in farm management and farm income. 相似文献
246.
Changes in pH and organic acids in mucilage of Eriophorum angustifolium roots after exposure to elevated concentrations of toxic elements 总被引:1,自引:0,他引:1
M. Tariq Javed Eva Stoltz Sylvia Lindberg Maria Greger 《Environmental science and pollution research international》2013,20(3):1876-1880
The presence of Eriophorum angustifolium in mine tailings of pyrite maintains a neutral pH, despite weathering, thus lowering the release of toxic elements into acid mine drainage water. We investigated if the presence of slightly elevated levels of free toxic elements triggers the plant rhizosphere to change the pH towards neutral by increasing organic acid contents. Plants were treated with a combination of As, Pb, Cu, Cd, and Zn at different concentrations in nutrient medium and in soil in a rhizobox-like system for 48–120 h. The pH and organic acids were detected in the mucilage dissolved from root surface, reflecting the rhizospheric solution. Also the pH of root–cell apoplasm was investigated. Both apoplasmic and mucilage pH increased and the concentrations of organic acids enhanced in the mucilage with slightly elevated levels of toxic elements. When organic acids concentration was high, also the pH was high. Thus, efflux of organic acids from the roots of E. angustifolium may induce rhizosphere basification. 相似文献
247.
Guillaume Stoltz Jean-Pierre Gourc Laurent Oxarango 《Waste management (New York, N.Y.)》2010,30(8-9):1439-1449
Following the basics of soil mechanics, the physico-mechanical behaviour of municipal solid waste (MSW) can be defined through constitutive relationships which are expressed with respect to three physical parameters: the dry density, the porosity and the gravimetric liquid content. In order to take into account the complexity of MSW (grain size distribution and heterogeneity larger than for conventional soils), a special oedometer was designed to carry out laboratory experiments. This apparatus allowed a coupled measurement of physical parameters for MSW settlement under stress. The studied material was a typical sample of fresh MSW from a French landfill. The relevant physical parameters were measured using a gas pycnometer. Moreover, the compressibility of MSW was studied with respect to the initial gravimetric liquid content. Proposed methods to assess the set of three physical parameters allow a relevant understanding of the physico-mechanical behaviour of MSW under compression, specifically, the evolution of the limit liquid content. The present method can be extended to any type of MSW. 相似文献
248.
Pinning down vulnerability: from narratives to numbers 总被引:2,自引:0,他引:2
Social vulnerability analyses have typically relied upon narratives to capture the nuances of the concept. While narratives have enhanced our understanding of the multiple drivers of vulnerability, they have had limited influence on hazards and climate adaptation policy. This is partially a function of the different needs and goals of the policy and research communities. The former prioritises generalised quantitative information, while the latter is more concerned with capturing complexity. A theoretically driven and empirically tested quantitative vulnerability and capacities index (VCI) for use at the local scale is presented to help connect vulnerability research and policy. There are four versions of the index for use in rural and urban contexts at the household and community levels. There can be an infinite number of drivers of vulnerability, but the VCI draws upon 12 indicators to represent material, institutional and attitudinal aspects of differential vulnerability and capacities. 相似文献
249.
Daniel Campo Jose Molares Lucia Garcia Pino Fernandez-Rueda Claudia Garcia-Gonzalez Eva Garcia-Vazquez 《Marine Biology》2010,157(1):147-156
The alternation of glacial and interglacial events during the Pleistocene has produced changes in species distribution ranges
leading to bottlenecks and alterations of patterns of gene flow. The European stalked barnacle, Pollicipes pollicipes, is a sessile pedunculate cirripede that inhabits the rocky intertidal frame, from Senegal to the northwestern coast of France.
In this work, we have analyzed a fragment of the mitochondrial gene cytochrome c oxidase subunit I for 569 individuals of P. pollicipes in order to investigate whether the shifts in climatic conditions that occurred during the Pleistocene influenced the current
pattern of distribution of genetic variation of P. pollicipes. A pre-last glacial maximum pattern of demographic expansion was found, in concordance with many other North Atlantic marine
species. On the other hand, three potential glacial refugia were identified: North African coasts, northwestern Iberian Peninsula
and English Channel/Brittany. 相似文献
250.
An evaluation of the social organization and sexual system of eusocial species of Synalpheus has been hindered because it has not been possible to determine the sexual composition of colony helpers (workers). The external
sexual characters typically used to sex caridean shrimps are lacking in Synalpheus. We used SEM sexing technique to determine the sexual composition of helpers in colonies of Synalpheus regalis, S. rathbunae, S. chacei, S. rathbunae A (see Morrison et al. Mol Phylogen Evol 30:563–568, 2004), and S. filidigitus. Colonies consisted of both sexes and sex ratios of helpers generally conformed to 50:50 female to male. Females were characterized
by gonopores with U-shaped slits on the coxae of the third pereopods (first walking legs) while males had oval gonopore openings
on the coxae of the fifth pereopods (third or last walking legs). In S. chacei, S. filidigitus, and S. rathbunae A, a few helpers were found that had both male and female gonopores (intersexes). All three reproductive females (queens) of
S. filidigitus examined were intersexes. Sexing of helpers allowed us to test some hypotheses about sexual differences in helper morphology
that might indicate task specialization (division of labor). Male helpers were not different from female ones in body size
(except in S. regalis: males somewhat larger) and in fighting chela size. The lack of sexual dimorphism in these characters suggests no male–female
specialization in colony tasks such as defense. The presence of male and female helpers similar in size suggests that the
sexual system of these eusocial species is gonochoristic, although protandry of some sort in S. filidigitus can not be ruled out. The intersexuality observed in a few individuals may be due to developmental anomalies, protandry,
or even simultaneous hermaphroditism. Finally, the sexing technique allowed us to establish that new colonizers of unoccupied
sponges in S. rathbunae are a single male and female of helper size. 相似文献