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生物接触氧化法处理污水的一种新型填料—悬浮填料   总被引:41,自引:0,他引:41  
综述了国内外生物接触氧化法处理污水的一种新型填料-悬浮填料的研究现状,分析了此类填料的特点及其在污水处理中的应用情况,提出了改善此类填料性能的研究趋势。  相似文献   
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Fisheries management is the practice of analyzing and selecting options to maintain or alter the structure, dynamics, and interaction of habitat, aquatic biota, and man to achieve human goals and objectives. The theory of fisheries management is: managers or decision makers attempt to maximize renewable `output' from an aquatic resource by choosing from among a set of decision options and applying a set of actions that generate an array of outputs. Outputs may be defined as a tangible catch, a fishing experience, an existence value, or anything else produced or supported by renewable aquatic resources. Overall output is always a mix of tangible and intangible elements. However defined, management goals and objectives are essential components of fisheries management or any other field of renewable natural resource management. Reaching consensus on management goals and objectives has never been a simple task. Beyond the broad and often conflicting goals of an agency, managers must decide who should set specific management objectives — agency personnel, the public, or a combination of the two. Historically, rhetoric aside, fisheries managers in North America nearly always have consulted with professionals in governmental roles to set management objectives. In a strongly pluralistic society, this often resulted in protracted political and legal conflict. Increasingly, there are calls for use of risk assessment to help solve such ecological policy and management problems commonly encountered in fisheries management. The basic concepts of ecological risk assessment may be simple, but the jargon and details are not. Risk assessment (and similar analytical tools) is a concept that has evoked strong reactions whenever it has been used. In spite of the difficulties of defining problems and setting management objectives for complex ecological policy questions, use of risk assessment to help solve ecological problems is widely supported. Ecological risk assessment will be most useful (and objective) in political deliberations when the policy debate revolves around largely technical concerns. To the extent that risk assessment forces policy debate and disagreement toward fundamental differences rather than superficial ones, it will be useful in decision making.  相似文献   
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Large‐scale change in human values and associated behavior change is believed by some to be the ultimate solution to achieve global biodiversity conservation. Yet little is known about the dynamics of values. We contribute to this area of inquiry by examining the trajectory of values affecting views of wildlife in North America. Using data from a 19‐state study in the United States and global data from the Schwartz Value Survey, we explored questions of value persistence and change and the nature of attitudinal responses regarding wildlife conservation issues. We found support, based on subjects’ ancestry, for the supposition that domination is a prevalent American value orientation toward wildlife that has origins in European Judeo‐Christian traditions. Independent of that effect, we also found indications of change. Modernization is contributing to a shift from domination to mutualism value orientations, which is fostering attitudes less centered on human interests and seemingly more consistent with a biocentric philosophy. Our findings suggest that if value shift could be achieved in a purposeful way, then significant and widespread behavior change believed necessary for long‐term conservation success may indeed be possible. In particular, greater emphasis on mutualism values may help provide the context for more collaborative approaches to support future conservation efforts. However, given the societal forces at play, it is not at all clear that human‐engineered value shift is tenable. Instead of developing strategies aimed at altering values, it may be more productive to create strategies that recognize and work within the boundaries of existing values. Whereas values appear to be in a period of flux, it will be difficult to predict future trends without a better understanding of value formation and shift, particularly under conditions of rapid social‐ecological change.  相似文献   
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Safety assessments for radioactive waste disposal require estimations of the migration of radionuclides in soils. The influence of humic acid (HA) on the sorption of uranium in its +4 oxidation state to kaolin has been examined from pH 4 to 8, with HA concentrations of 15–200 ppm. In the absence of HA, 20–40% of the U(IV) was in solution, with more sorption occurring at higher pH. The presence of HA solubilised up to 90% of the uranium with higher solubilities at higher HA concentrations and higher pH values. Uranium sorption was mapped against HA sorption, and it was found that there was a lower level of U(IV) sorption than can be accounted for by just measuring HA sorption. However, this effect got less marked as the pH rose. Sensitivity analysis indicated that the fraction of surface-bound HA is the controlling parameter for modelling in these systems.  相似文献   
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OBJECTIVE: To determine whether DUI offenders can better avoid future drinking and driving by controlling their vehicle usage rather than by controlling their drinking. METHODS: Using a randomized experimental post-test only design, 9,571 first-time DUI offenders were randomly assigned to receive one of two 12-hour educational programs: a traditional DUI curriculum or the PARC (Preventing Alcohol-Related Convictions) curriculum, which uses a novel theoretical approach to preventing DUI recidivism. Whereas traditional programs focus on participants controlling their drinking to avoid future drinking and driving, the PARC curriculum focuses on participants controlling their driving. Instead of trying to control alcohol consumption after driving to a drinking venue (previously found to be a flawed strategy), PARC teaches students to make a decision before leaving home not to drive to a drinking event, thus greatly limiting the possibility of drinking and driving. Driving records were obtained from the Florida Department of Motor Vehicles using driver's license numbers to assess DUI recidivism rates among the students in the PARC and Traditional curricula for the first year following program participation and again at 2 years post-intervention. RESULTS: Binary logistic regression analyses revealed that offenders receiving the PARC curriculum exhibited significantly lower 1-year and 2-year recidivism rates than those receiving the Traditional curriculum. The effect was consistent across two different measures of recidivism, and across gender, race, ethnicity, and location. CONCLUSION: Results suggest that the PARC educational approach may be more effective than the traditional approach in reducing DUI recidivism.  相似文献   
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Alternatives assessment is becoming increasingly popular to evaluate the potential environmental and human health hazards of materials. A three step process was used to identify and evaluate alternative products for a children's furniture manufacturer. An alternatives assessment framework was developed to analyze alternative mattresses. The framework specifically addresses those environmental and safety attributes applicable to the product and the product components in accordance with the product’s intended use. The result of the assessment allowed the manufacturer to select the most environmentally friendly alternative and eliminate polyvinyl chloride from their product.  相似文献   
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Hazardous chemicals are pervasive in household disinfectant products. Many ingredients have established associations with acute and chronic human health conditions as well as with environmental damage. Although these associations are suggested but not proven, they are of great concern. This article describes the application of the precautionary principle to the selection of an anti-microbial active ingredient for a botanical disinfectant when significant uncertainty exists around the hazard and risk of traditional disinfectant active ingredients. We show that application of the precautionary principle does not stifle innovation and facilitates a responsible approach to product development.  相似文献   
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As the economic costs of energy and the negative externalities associated with the combustion of fossil fuels threaten the economic viability of greenhouses in northern climates there is a renewed interest in the use of waste heat. This paper presents a technical and economic methodology to determine the viability of establishing waste heat greenhouses using the waste heat from industrial processes in northern climates. A case study is presented of an exchange between a tomato greenhouse and a flat glass manufacturing plant, which found the waste heat system is significantly more economic to operate than a purely natural gas system.  相似文献   
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