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21.
The risk assessment of bisphenol A (BPA) on the development of offspring of humans is an important issue. There have been some reports on the fate of BPA in rodents, but information on the BPA level in fetal organs essential for the extrapolation to humans is inadequate. In the present study, we investigated the distribution pattern of 14C-BPA-derived radioactivity in fetal tissues following administration of 10?mg/kg 14C-BPA to the pregnant mice. The radioactivity was rapidly transferred through placenta and distributed to all fetal organs including reproductive organs and brains in a similar level. The concentration declined slowly compared with dams. Analysis of metabolites in fetuses showed that a fraction of BPA was unexpectedly large compared to the maternal blood. There was no clear effect of the fetal position in a uterus to influence the radioactivity concentration in whole fetuses. The dose dependence of pharmacokinetics should be recognized to extrapolate the pharmacokinetic result from animal experiments at high doses to humans at low doses. Similar experiments were conducted with an addition of two doses, 1 and 100?mg/kg, respectively. The pharmacokinetics seemed to be linear between 1 and 10?mg/kg, although at 100?mg/kg BPA was absorbed slowly and the radioactivity concentrations in fetuses were much higher than expected based on the linear dose dependence. Repeated doses were administered to pregnant mice since humans are exposed to BPA chronically. Radioactivity level in most of the fetal tissues on repeated administration was higher than single administration.  相似文献   
22.
Deliberative monetary valuation (DMV) methods can support environmental decision making by enabling the exchange of arguments and information to produce more democratic outcomes. The product of a valuation may be an array of expressions of willingness to pay (WTP) by individuals or a collectively agreed monetary value. Concerns have been raised, however, as to whether this product is an outcome of thoughtful and independent decision-making or influenced by social pressures to conform. Our study examines this issue and addresses concerns about the use of DMV, based on a public deliberation of forest conservation in Colombia. We analyzed the impacts of social conformity on WTP under two different decision scenarios: individual and collective. The results suggest that the impacts of social conformity are greater when a collective decision is required. These findings indicate that tensions between the differing goals of DMV could undermine its democratic promise.  相似文献   
23.
When we try to estimate future environmental costs resulting from our current economic activities,we usually calculate the present value of the consequences for our future generations by utilizing a discount rate as a standard economic procedure.The popularity of this procedure is solely supported by its simplicity which assumes:(1)a perfect financial market over even 100 years,and(2)existence of a stable time preference between two consecutive periods for an individual consumer.An apparent deficiency of this approach is that the present value of life quality of future generations varies to a large extent along an arbitrarily chosen discount rate.As a matter of fact,the discount rate,which could reflect the time preference as2%or 5%,matters when we predict current strategies of environmental protection for future generations.Simply applying a discount rate to evaluate the quality of our future generation,without clarifying the actual production mechanism behind this,is almost to the same as ignoring the fact that all of the goods are produced through an actual production process and that environmental degradation reduces the efficiency of that process.The greatest concern for our future generations should not be given by an assumed discount rate,since the discount rate itself is determined by financial market conditions at certain points in time.  相似文献   
24.
This study examines the distribution, composition, and structure of benthic communities in nine shallow-water semienclosed embayments on Cape Cod, southeastern Massachusetts. The spatial patterns were used to associate benthic characteristics with local environmental factors. Field data from multiple years were collected to measure macrofaunal abundance, community composition, and environmental characteristics. Multivariate statistics were used to analyze the spatial variations of species composition and the abundance of benthic macrofauna. Canonical ordination, specifically redundancy analysis, was used to determine the relative importance of the environmental factors (nutrients and habitat factors) being studied. The analyses demonstrate that the benthic communities in the shallow tidal embayments are clearly clustered in association with the local environments. Species composition and community structure of the benthic macrofauna are significantly correlated with water column parameters, especially with phytoplankton biomass, total nitrogen, and dissolved oxygen.  相似文献   
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26.
Major disasters, such as bushfires or floods, place significant stress on scarce public resources. Climate change is likely to exacerbate this stress. An integrated approach to disaster risk management (DRM) and climate change adaptation (CCA) could reduce the stress by encouraging the more efficient use of pooled resources and expertise. A comparative analysis of three extreme climate-related events that occurred in Australia between 2009 and 2011 indicated that a strategy to improve interagency communication and collaboration would be a key factor in this type of policy/planning integration. These findings are in accord with the concepts of Joined-up Government and Network Governance. Five key reforms are proposed: developing a shared policy vision; adopting multi-level planning; integrating legislation; networking organisations; and establishing cooperative funding. These reforms are examined with reference to the related research literature in order to identify potential problems associated with their implementation. The findings are relevant for public policy generally but are particularly useful for CCA and DRM.  相似文献   
27.
Food and Environmental Virology - Influenza A virus (IAV) infection is perennially one of the leading causes of death worldwide. Effective therapy and vaccination are needed to control viral...  相似文献   
28.
Relationships between flooding frequency, flooding duration, litter moisture levels, and litter decay rates were investigated across the natural hydrologic gradient common to intertidal salt marshes. The effects on litter decay of natural and experimental alterations of litter moisture content were assessed in both field litterbag experiments (conducted in a southern New Jersey salt marsh from 1989 to 1990) and laboratory incubations (1990). Overall, tidally mediated litter moisture content was the dominant factor controlling litter decay throughout the vegetated marsh. Rates of carbon loss were most closely related to litter moisture levels (r=0.84), which were directly related to flooding frequency (r=0.66) and duration (r=0.63). Litter moisture levels were related to elevation within the tidal range due to increasing surface levation from creekbank to high marsh (ca. 54 cm) and height of litter above the sediment surface. Carbon losses from litter of short and tall form Spartina alterniflora Loisel. and S. patens (Aiton) Muhl. along the marsh elevation gradient indicate that while some of the variations in decay rates may be due to litter type, litter moisture accounted for most of the observed variation between marsh zones and within each litter type. Mousture levels are also affected by the water retention capacity of each litter type, which may also secondarily influence decay rates. Short-term incubations of litter indicated that CO2 evolution was positively related to moisture content with negligible respiration at moisture levels below 15% (fresh mass), increasing to a maximum between 65 and 75% depending upon litter type. Since most Spartina spp. litter remains above the marsh surface where it maintains a lower moisture content than surface litter, the use of surface litterbags may overestimate rates of carbon loss in some systems. In addition, since changes in elevation of only a few centimeters had significant effects on both litter moisture levels and decay rates, slight changes in tidal regime may have important consequences for organic matter cycling in salt marshes by affecting litter decomposition processes.  相似文献   
29.
Journal of Material Cycles and Waste Management - In this study, we developed a one-pot wet ball-milling method for the recovery of highly pure copper wire, poly(vinyl chloride) (PVC) coating, and...  相似文献   
30.
A fine porcelain open-cell photo-catalytic filter with titanium dioxide (TiO(2)) was evaluated for sterilization and sanitation of bio-polluted industrial water. In simulated seawater industrial effluent samples, the populations of Escherichia coli and Vibrio parahaemolyticus quickly decreased and reached non-detectable level within 10min. In seawater effluents from a seaweed processing plant, the bacterial populations in two samples quickly decreased by more than 10(3). In another two samples the decreases were slow and lowered by less than 10(2). Using fluorescence microscopy, it was indicated that the bacterial cells treated with photo-catalytic TiO(2) were damaged. In addition, the protein concentration in simulated seawater effluent slowly decreased using the photo-catalytic TiO(2) reaction; and reached similar concentrations as seawater near cultured seaweed beds. These results indicate that using a reactor with a TiO(2) photo-catalyst filter was effective for the sanitation of seawater effluents.  相似文献   
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