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271.
Despite its negative effects, formalin has been often used for the expulsion of earthworms due to its high efficiency; however it is not known whether it will affect any significant measurable molecular processes in sampled earthworms. The aim of this research was to investigate effects of formalin on the activities of chosen molecular biomarkers in Eisenia andrei earthworms previously exposed to temephos. Additionally, the inhibitory effect of temephos, hitherto evaluated only on laboratory-bred earthworm species, was confirmed on two earthworm species obtained from their natural environment – Dendrobaena octaedra and Lumbricus rubellus. Earthworms were first exposed to the sub-lethal concentration of temephos for 2 h and then to formalin 15 min in order to simulate the sampling procedure. Besides acetylcholinesterase (AChE) inhibition – a known biomarker of exposure to organophosphate insecticides – the concentration of oximes and the activities of catalase (CAT) and efflux pump were measured. Results showed that in all species temephos caused inhibition of AChE and CAT activity. Exposure of E. andrei to formalin caused inhibition of AChE, however after post-exposure to formalin for 15 min significant increase in AChE activity was recorded. Similar results were obtained with the measurement of oximes concentrations. Exposure to only formalin and combination of temephos (2 h) and formalin (15 min) led to an increase in the CAT activity. The obtained results showed that exposure to formalin during the sampling could affect measured molecular biomarkers and also may change effects caused by exposure to temephos. 相似文献
272.
Iván N. Pérez-Maldonado Antonio Trejo-Acevedo Sandra Teresa Orta-García Ángeles C. Ochoa-Martinez José Antonio Varela-Silva Francisco Javier Pérez-Vázquez 《Journal of environmental science and health. Part. B》2013,48(2):87-93
The aim of this study was to assess the levels of dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) in the blood of children living in the southeastern region of Mexico. In this study, we found high levels of DDT and its principal metabolite (DDE) in the blood of children residing in the communities studied. The levels of total DDT found in our study ranged from 4,676.4 ng/g lipid to 64,245.2 ng/g lipid. All of the children in the study had detectable levels of DDT and/or DDE. In conclusion, our data indicate that children living within the study areas are exposed to high levels of DDT and DDE. Moreover, these results can be used as a trigger to revisit local policies on environmental exposures. 相似文献
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Spatial Targeting of Agri-Environmental Measures: Cost-Effectiveness and Distributional Consequences
Sandra Uthes Bettina Matzdorf Klaus Müller Harald Kaechele 《Environmental management》2010,46(3):494-509
Agri-environmental measures are payments to farmers to reduce environmental risks or to preserve cultivated landscapes. These
measures are codified in European Union regulations. Poor spatial targeting is one of the major causes of low cost-effectiveness
in agri-environmental measures. Existing studies on spatial targeting focus primarily on selected individual measures; hence,
they do not allow for conclusions at the program level, where the planning and implementing of decisions on a number of different
measures has to be made. In this study, we analyzed the impacts of two spatial targeting options (targeting of erosion-reducing
measures on erosion vulnerable areas; targeting of grassland extensification on N-pollution vulnerable areas) on the cost-effectiveness
of the single measures and the entire agri-environmental program of the federal state of Brandenburg in Germany. The methodological
steps included an analysis of empirical data on land use and program participation, an expert-based environmental impact assessment
and a spatial allocation procedure based on linear programming. The environmental impact assessment delivered goal-specific
index values for each measures-land parcel combination expressing the suitability of the measures for contributing to four
regionally relevant program objectives. The cost-effectiveness of the measures and the program were calculated by putting
budgetary costs in relation to the achieved environmental index sum. The calculated cost-effectiveness of the program in 2006
was 89.6% of the simulated optimal cost-effectiveness. The spatial targeting of erosion-reducing measures on erosion vulnerable
areas caused an increase in the cost-effectiveness at the measures level and almost no changes at the program level. The spatial
targeting of grassland extensification on N-pollution vulnerable areas, despite also improving the cost-effectiveness of this
measure, had negative effects on the cost-effectiveness of the program. 相似文献
277.
Lavorel Sandra Grigulis Karl Leitinger Georg Kohler Marina Schirpke Uta Tappeiner Ulrike 《Regional Environmental Change》2017,17(8):2251-2264
Regional Environmental Change - Land use and spatial patterns which reflect social-ecological legacies control ecosystem service (ES) supply. Yet, temporal changes in ES bundles associated with... 相似文献
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Mesograzers are thought to play a critical role in seagrass beds by preventing overgrowth of ephemeral algae. On the Swedish
west coast, eelgrass Zostera marina has decreased in recent decades as a result of eutrophication and increased growth of macroalgal mats (mainly filamentous
Ulva spp. and Ectocarpales), with no indication of grazer control of the algae. The aim of this study was to investigate the ability
of the amphipod Gammarus locusta to control algal blooms during nutrient-enriched and ambient conditions, using a combination of laboratory, field and model
studies. Laboratory experiments demonstrated that juvenile and adult G. locusta could consume both Ulva spp. and Ectocarpales, but that consumption of Ulva spp. was significantly higher. Cannibalism was common in individual treatments involving multiple size-classes of G. locusta, but only large, male gammarids consumed smaller juveniles in the presence of Ulva spp. as an alternative food source. However, no negative effects of cannibalism were found on total grazing impact. A model
using size-specific grazing rates and growth rates of G. locusta and of Ulva spp. suggests that approximately 62 young juvenile, or 27 adult G. locusta are needed per gram DW of Ulva spp. to control the algal growth during ambient nutrient conditions, and approximately 2.6 times as many gammarids during
enhanced nutrient conditions. On the Swedish west coast, densities and mean sizes of G. locusta in eelgrass beds are below these critical values, suggesting that the gammarids will not be able to control the growth of
the filamentous macroalgae. However, in the field cage experiment, immigration of juveniles and reproduction of encaged adult
G. locusta resulted in unexpectedly high densities of G. locusta (>4,000 individual m−2), and very low biomass of Ulva spp. in both ambient and nutrient-enriched treatments. Although the high numbers of juveniles in all cages precluded any
significant treatment effects, this suggests that in the absent of predators, the population of G. locusta can grow significantly and control the biomass of Ulva spp. Furthermore, low grazing of Ectocarpales in the laboratory and high biomass of these filamentous brown algae in the
field indicate a preference for the more palatable green algae Ulva spp. This study indicates that the high grazing capacity of G. locusta, in combination with high reproduction and growth rates, would allow the amphipod to play a key role in Z. marina ecosystems by controlling destructive blooms of filamentous green algae. However, high predation pressure appears to prevent
large populations of G. locusta in eelgrass beds on the Swedish west coast today. 相似文献
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