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41.
A study on the possibility of recycling waste materials, such as olive husk, the solid phase derived from an olive oil mill, in blend with thermoplastic polymers to produce new materials for manufacturer of, for example, containers and formworks, has been carried out. The present paper describes the methodology used for the preparation and the characterization of composite samples prepared by mixing various percentages of olive husk and polypropylene. A screening on the chemical-physical characteristics of the olive husk is reported, as well as a set of tests applied to evaluate the mechanical properties of the manufactured products obtained.  相似文献   
42.
Combined archaeological and ecological investigations in a large ancient oak forest in Central France have revealed a dense network of ancient human settlements dating from the Roman period. We demonstrate a strong correlation between present-day forest plant diversity patterns and the location of Roman farm buildings. Plant species richness strongly increases toward the center of the settlements, and the frequency of neutrophilous and nitrogen-demanding species is higher. This pattern is paralleled by an increase in soil pH, available P, and delta(15)N, indicating the long-term impact of former agricultural practices on forest biogeochemical cycles. These extensive observations in a forested region on acid soils complement and confirm previous results from a single Roman settlement on limestone. Ancient Roman agricultural systems are increasingly being identified in contemporary French forests; the broad extent and long-lasting effects of previous cultivation shown in this study require that land-use history be considered as a primary control over biodiversity variations in many forest landscapes, even after millennia of abandonment.  相似文献   
43.
Burning fossil fuel in the North American continent contributes more to the CO2 global warming problem than in any other continent. The resulting climate changes are expected to alter food production. The overall changes in temperature, moisture, carbon dioxide, insect pests, plant pathogens, and weeds associated with global warming are projected to reduce food production in North America. However, in Africa, the projected slight rise in rainfall is encouraging, especially since Africa already suffers from severe shortages of rainfall. For all regions, a reduction in fossil fuel burning is vital. Adoption of sound ecological resource management, especially soil and water conservation and the prevention of deforestation, is important. Together, these steps will benefit agriculture, the environment, farmers, and society as a whole.  相似文献   
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45.
The subcellular distribution of technetium was studied using the seastar Marthasterias glacialis which had previously ingested prey labelled with 95mTc either as pertechnetate (VII) or in the reduced state (IV). The majority of the Tc [98% (IV) and 96% (VII)] was taken up and retained in the pyloric caeca, the gland responsible for digestive and food storage processes. Differential centrifugation and separation techniques have demonstrated that, at the subcellular level, technetium in the pyloric caeca was largely associated with the lysosomes. 95mTc (IV) was distributed between the lysosomes and the soluble fraction to roughly the same degree, whereas pertechnetate was more strongly associated with the lysosomal fraction. Chromatography of the cytosol by gel filtration indicated the presence of two distinct protein compounds which were responsible for binding virtually all of the technetium in the soluble fraction. Technetium had a greater relative affinity for the low molecular weight compound, more so for Tc (VII) than for Tc (IV). This anionic protein had an apparent molecular weight of approximately 10 000, and thus may play a role in metal detoxification mechanisms at the cellular level.  相似文献   
46.
The rhythmicity of intracellular digestion was examined in two sublittoral populations of Ostrea edulis L. On the West coast of Ireland. During 12 h cycles at each station, 20 oysters were collected each hour, grouped as sub-samples of 5, facing each of the 4 cardinal points of the compass. A segment of digestive diverticula from each oyster was examined histologically and classified according to the digestive phases of the tubules. Oysters at both stations exhibited fluctuations in digestive activity which were not correlated with tidal ebb and flow nor with orientation to tidal currents. A relationship between variations in suspended particulate matter concentration in the water body and digestion is proposed. It is suggested that increases in the levels of particulate matter, by stimulating feeding, cause a significant increase in the proportion of absorptive-phase tubules 4 to 6 h later.  相似文献   
47.
Bacterial and meiofaunal abundance and biomass and their response to the disturbance induced by fish-farm biodeposition were investigated from March to October 1997 on a monthly basis at two stations of the Gaeta Gulf (Tyrrhenian Sea, Mediterranean Sea). The biopolymeric fraction of the organic matter was characterized by high concentrations which was similar at both fish-farming-impacted and control stations. Similarly, bacteria accounted for a small fraction of the biopolymeric organic carbon (< 1%), while the contribution due to auto-fluorescent cell biomass (i.e. prokaryotic and eukaryotic cells displaying auto-fluorescence) to the total biopolymeric carbon was quantitatively negligible (< 0.1%). Benthic bacteria appear to be sensitive to organic enrichment as their abundance increased significantly beneath the cage, whilst numbers of meiofauna was lower than in the control. Changes occurred also in terms of individual nematode biomass that increased as result of the biodeposition. A particularly useful tool appeared to be represented by the ratio of benthic auto-fluorescent cells to bacterial abundance, bacteria to meiofaunal biomass and auto-fluorescent cells to meiofauna biomass. All these parameters described well the impact due to biodeposition on the benthic environment as their ratios displayed significantly higher values in farm sediments, but recovered rapidly (15 days) to values observed in the control (i.e. undisturbed conditions) immediately after cage removal. Changes observed in the present study highlight that the increased organic loading determined a shift of the relative contribution of the different benthic components to the total biopolymeric carbon, so that in highly impacted systems total benthic biomass becomes increasingly dominated by microbial components.  相似文献   
48.
49.
Two autochthonous clams, Venerupis aurea laeta and Cerastoderma edule/glaucum, collected for a period of 1 year, from May 2007 to January 2008, were studied in the Cape Peloro lagoon. On the samples, it was evaluated the presence of pathogenic microorganisms and proteins, lipids and yield edible part were determined. It was evaluated the concentration of mineral elements (Cd, Cu, Mn, Se, Pb, Zn) and organic contaminants (∑DDT and PCBs). Salmonella is never present in any sample. Total and faecal coliform values have always been under law limits for alive bivalves mussels production and sale. Zn, Cu, Cd and Pb levels were found in clams where they are slightly lower too. Both species do not show significant changes for Mn and Se. DDT and PCBs traces were discovered in Ganzirri Lake’ samples, but in all observed cases, they were below law limits. As a result of all these observations, it is clear that, in recent years, the bivalve’s use of Ganzirri Lake does not denote toxicological risk to human health.  相似文献   
50.
This paper discusses monitoring the waste destruction efficiency of hazardous waste incinerators. The particular problem is to ensure that incinerators do not release, without detection, significant quantities of waste as a result of operating fluctuations or equipment degradation. To detect these conditions, continuous, automated, and real-time source monitoring is required. Detection of degraded performance by monitoring and measuring waste compounds directly is not presently possible on a continuous basis. An alternative is to use commercially available continuous monitors to measure combustion intermediates (e.g., CO or hydrocarbons) and thereby infer waste destruction efficiency. Required, however, is a correlation between the emission of intermediates and the emission of waste. In this paper, the response of a number of these continuous monitors is compared with waste destruction efficiency measurements from a laboratory scale, liquid-spray incinerator operated on fuel oil doped with model waste compounds: benzene, chlorobenzene, acrylonitrile, and chloroform. Total hydrocarbon and CH4 measurements are found to vary with waste emission in a nearly linear manner; however, a substantial increase in CO emission occurs before a significant amount of waste is released. These results suggest that CO may serve as an indicator of the approach of waste release, while total hydrocarbons may provide an indicator of immediate waste release.  相似文献   
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