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1.
The technique of thermal desorption (TD)–GC/MS was evaluated for measuring airborne, 4–6 ring polycyclic aromatic hydrocarbons (PAHs) collected onto quartz filters. TD provides a more readily automated and sensitive alternative to traditional solvent extraction, decreasing the time/cost of analysis and reducing the risk of analyte loss or sample contamination. The developed method was successfully applied to the analysis of PAH standard solutions loaded on sorbent tubes packed with quartz wool and the graphitized carbon black sorbent Carbograph2. The optimized method showed high desorption efficiency over the whole range of target PAHs with good precision, linearity and sensitivity. The proposed method was verified on an urban dust Standard Reference Material (SRM 1649a); the experimentally determined concentrations agreed with the certified ranges (95% confidence limit) for all target compounds except benzo[a]anthracene, which fell just outside the narrow certified range. The desorption efficiency and the reproducibility of the method was evaluated by analysing pieces of real sample filters sampled from urban air for a period of 24 h. The results confirmed the homogeneity of the filter and showed high recovery efficiencies for all target PAHs.  相似文献   
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Anaerobic digestion is mainly used for sewage sludge stabilization and for treatment of waste that has a high organic content. It also represents a powerful method for obtaining energy by means of natural gas production. Co-digestion particularly combines different organic substrates to generate a homogeneous mixture as input to the anaerobic reactor in order to increase process performance. Reactions kinetics and knowledge of process analysis represent the keys for good planning and correct management. In this paper a model to simulate the main reactions involved in anaerobic co-digestion is presented. The model was created to analyse the possible performance of the treatment plant in Olmeto, Marsciano (Perugia) in Italy. The plant is still in an experimental phase with regard to the co-digestion process and numerical simulations represent a useful tool during development of the correct management procedures for the operational phase and a good methodoly for addressing further pilot plant experiments.  相似文献   
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Precaution,uncertainty and causation in environmental decisions   总被引:1,自引:0,他引:1  
What measures of uncertainty and what causal analysis can improve the management of potentially severe, irreversible or dreaded environmental outcomes? Environmental choices show that policies intended to be precautionary (such as adding MTBE to petrol) can cause unanticipated harm (by mobilizing benzene, a known leukemogen, in the ground water). Many environmental law principles set the boundaries of what should be done but do not provide an operational construct to answer this question. Those principles, ranging from the precautionary principle to protecting human health from a significant risk of material health impairment, do not explain how to make environmental management choices when incomplete, inconsistent and complex scientific evidence characterizes potentially adverse environmental outcomes. Rather, they pass the task to lower jurisdictions such as agencies or authorities. To achieve the goals of the principle, those who draft it must deal with scientific casual conjectures, partial knowledge and variable data. In this paper we specifically deal with the qualitative and quantitative aspects of the European Union's (EU) explanation of consistency and on the examination of scientific developments relevant to variability and uncertain data and causation. Managing hazards under the precautionary principle requires inductive, empirical methods of assessment. However, acting on a scientific conjecture can also be socially unfair, costly, and detrimental when applied to complex environmental choices. We describe a constructive framework rationally to meet the command of the precautionary principle using alternative measures of uncertainty and recent statistical methods of causal analysis. These measures and methods can bridge the gap between conjectured future irreversible or severe harm and scant scientific evidence, thus leading to more confident and resilient social choices. We review two sets of measures and computational systems to deal with uncertainty and link them to causation through inductive empirical methods such as Bayesian Networks. We conclude that primary legislation concerned with large uncertainties and potential severe or dreaded environmental outcomes can produce accurate and efficient choices. To do so, primary legislation should specifically indicate what measures can represent uncertainty and how to deal with uncertain causation thus providing guidance to an agency's rulemaking or to an authority's writing secondary legislation. A corollary conclusion with legal, scientific and probabilistic implications concerns how to update past information when the state of information increases because a failure to update can result in regretting past choices. Elected legislators have the democratic mandate to formulate precautionary principles and are accountable. To preserve that mandate, imbedding formal methods to represent uncertainty in the statutory language of the precautionary principle enhances subsequent judicial review of legislative actions. The framework that we propose also reduces the Balkanized views and interpretations of probabilities, possibilities, likelihood and uncertainty that exists in environmental decision-making.  相似文献   
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Animal wastes from intensive farming are generally collected for field fertilisation. They may contain drugs that can become soil pollutants. To evaluate the possible effects of such contamination in terrestrial systems, sulphadimethoxine has been subjected to laboratory tests (in vitro, synthetic medium, and soil) using seeds of barley (Hordeum distichum L.). The drug suppressed normal post-germinative development and growth of roots and leaves in both test conditions; this effect was dependent on the bioaccumulation rate, which was higher on synthetic medium than in soil. Bioaccumulation was higher in roots than foliage and this was markedly evident in soil and, in particular, in soils with a low humus content. The environmental risk of sludge application on soils and the possible contamination of food chains are discussed.  相似文献   
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Prenatal diagnosis of heterozygous achondroplasia at 25 weeks is described. First-level fetal ultrasonography demonstrated short long bones of the lower limbs. Second-level examination showed a large head; shortened femur, fibula, and tibia; a ‘trident’-shaped hand; and an abnormal facial profile.  相似文献   
9.
Recycling of plastics is a big issue in terms of environmental sustainability and of waste management. The development of proper technologies for plastic recycling is recognised as a priority. To achieve this aim, the technologies applied in mineral processing can be adapted to recycling systems. In particular, the improvement of comminution technologies is one of the main actions to improve the quality of recycled plastics. The aim of this work is to point out suitable comminution processes for different types of plastic waste. Laboratory comminution tests have been carried out under different conditions of temperature and sample pre-conditioning adopting as refrigerant agents CO2 and liquid nitrogen. The temperature has been monitored by thermocouples placed in the milling chamber. Also different internal mill screens have been adopted. A proper procedure has been set up in order to obtain a selective comminution and a size reduction suitable for further separation treatment. Tests have been performed on plastics coming from medical plastic waste and from a plant for spent lead batteries recycling. Results coming from different mill devices have been compared taking into consideration different indexes for representative size distributions. The results of the performed tests show as cryo-comminution improves the effectiveness of size reduction of plastics, promotes liberation of constituents and increases specific surface size of comminuted particles in comparison to a comminution process carried out at room temperature.  相似文献   
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Behind humanitarian assistance and disaster relief (HADR) efforts are governance networks of actors working together to facilitate, coordinate, and deliver joint aid and response initiatives. Militaries are key stakeholders in these networks because of their unique capabilities, particularly in Southeast Asia. This paper explores the role of military governance networks in shaping HADR affairs. It presents a framework for examining military-to-military relational structures in humanitarian and disaster contexts using network theory and social network analysis. It also assesses the nature of military ties and their influence on two capability areas essential to humanitarian activities in the region: (i) the distribution of military assets and equipment used in HADR; and (ii) the coordination of HADR exercises and training. This paper seeks to provide insights into how governance network features and properties affect the capacity of ASEAN (Association of Southeast Asian Nations) militaries to use available resources efficiently and to achieve shared objectives in regional disaster response.  相似文献   
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