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111.
112.
The environmental impact of loss of natural stream and riparian habitat is of concern throughout the United States and Europe. Environmental impacts related to such activities as channelization of and levee construction along streams and rivers are particularly apparent in the Midwestern United States. The objective of the research presented here was to delineate the extent, relative degree of impact, and implications for management of channelization and levee construction along watercourses located in the state of Illinois. According to records maintained through the Illinois Streams Information System data base (Illinois Department of Conservation), nearly 25% of surface water resources in the state have been modified directly by channelization and/or levee construction. Reviews of agency records, elaboration of case histories, interviews with agency personnel, and inspections of impacted sites indicated that these alterations have occurred without the benefit of effective mitigation. Although permit records may provide suggestions for mitigation to be incorporated in the design of a particular project, permits issued generally do not require even minimal instream habitat and bank stabilization efforts in conjunction with channel alteration. Information derived from policy and case study analyses suggests that institutional constraints, rather than lack of particular understanding about mitigation, provide major barriers to protecting the state's surface water resources in terms of regulatory review, policy interpretation and implementation, and project evaluation. Recommendations for environmental management efforts regarding these and similar channel alterations are elaborated from these findings.  相似文献   
113.
This study assessed the incremental validity of different media for representing landscapes with significant dynamic elements. The experimental design independently varied the presence of motion and sound in different representations of a wild and scenic river in order to evaluate the adequacy or sufficiency of the surrogate to reflect physical changes in the landscape. Three representational conditions were identified: (1) video/sound, (2) video/no sound, and (3) static/no sound. A pilot study assessed the ability of the static images to represent river flow levels per se, and confirmed comparability with prior results (Brown & Daniel, 1989, Journal of Environmental Psychology, 7, 233–250). Scenic beauty judgments were then collected within each representational condition. Multiple regression analyses were used to determine the relationship of flow level to perceived scenic beauty for each representation condition. The results demonstrated that motion and sound, individually and conjointly, influenced judgements of scenic beauty for a landscape with a significant dynamic element.  相似文献   
114.
The traditional approach to water resources management for urban areas has been based on the examination of needs and the design of separate facilities for water supply, drainage, and waste water collection and treatment. The complexity and interaction among the separate systems required by a metropolitan area has complicated their management and promoted research interest in developing a methodology for better coordination. However, a more thorough evaluation of the problem reveals the real research need to be both more complicated and different in character than the problem in systems analysis suggested by the first superficial glance. Water management relates to the much broader problem of community design; when, where, and in what manner should new urban development take place. Furthermore, the character and needs of areas within the metropolis are constantly changing. The key distinctiveness of urban water management is the imperative for design and operation flexibility. The key research need is to develop new designs, operation procedures, and institutional arrangements to make the flexibility demanded by a dynamic urban community possible.  相似文献   
115.
Biological plugs are an innovative, low-intervention, in-situ bioremediation methodology for both saturated and unsaturated contaminated soils. They are modular in-ground immobilized microbe bioreactors designed to rapidly increase the oxidation of organic contaminants by placing an adapted consortia of microorganisms in close proximity to the contaminants of concern. The approach is versatile, in that contaminants can be remediated in-situ without the removal of existing structures as well as being able to efficiently and economically treat contaminants over a large area. Amine- and glycol-contaminated soils at gas sweetening plants, represent a significant problem in magnitude, prevalence, and risk along pipelines stretching through Canada's western provinces. A field pilot study was conducted at an isolated former gas sweetening plant in northwestern Alberta. Monoethyamine (MEA) and several glycols were successfully remediated in situ in a 138-day time frame. Soil toxicity was significantly reduced. The engineering challenges and associated economics of remediating such isolated sites are also presented.  相似文献   
116.
ABSTRACT

Public participation in the form of public meetings and written submissions has been criticised as a democratic ritual that fails to give citizens a real voice in government decisions. Participatory mapping and community surveys are alternative public participation (PP) methods that can augment legally required processes for land use planning. To date, there has been little evaluation research comparing the information content generated by required PP processes and alternative PP sources with respect to local land use decisions. Using multiple development projects from a case study community, we analysed and compared information generated from three different sources of public participation: (1) formal public comment (written submissions), (2) responses to community survey questions, and (3) land use preferences generated from participatory mapping. We found public comment strongly supported development while results from survey questions and participatory mapping methods revealed community ambivalence. The differences in public opinion are attributed to two key factors: the representativeness of participants in the PP process and the specific methods used for measuring public opinion. Community surveys and participatory mapping generated more accurate and representative community information compared to the formal PP process which was characterised by lower participation and vulnerability to special interest manipulation. For local government decision makers, the political risk of broadening PP information appears high relative to the risk of inaccurately assessing public opinion thus limiting adoption of alternative PP methods such as participatory mapping.  相似文献   
117.
The effects of predominant currents on the morphology of coral reefs has been studied in the leeward patch reefs of Anegada, British Virgin Islands. Measurements of current velocity and direction and sediment characteristics together with mapping of approximately 31 patch reefs within a 2 km2 area suggest that even under relatively low but constant current velocities (surface current 20 cm sec-1) the major reef-building corals show definite distribution patterns on the reef. The currents also appear to be responsible, in part, for marked orientation and elongation of patch reefs in a north-west/ south-east direction and for a gradation of patch-reef type across the study area.  相似文献   
118.
Odors emananting from animal production facilities are the primary environmental cause for complaint resulting in great corrective expense and, in many instances, facility closure. The current state-of-the-art of odor control technology ranges from intensive waste management and good housekeeping practices to chemical treatment and facility isolation. These controls at best only limit the generation and/or quality of animal production odors. The most effective odor limiting technologies are the most cost intensive. Therefore, methods used are dependent upon the seriousness of the situation and the cost-benefit that may be derived from their use.Original facility design and site selection consideration are of great importance to the existence of confined animal feeding enterprises with a non-farm population which is encroaching at increasing rates into rural areas. Land use planning and zoning restrictions for agricultural/animal feeding purposes may well be the ultimate odor control tool of the future for newly instituted facilities. Extensive basic and applied research is required to provide adequate technology for use by existing facilities.  相似文献   
119.
Lead poisoning of waterfowl from direct ingestion of wetland mine tailings has been reported at the Coeur d'Alene River basin in Idaho. A greenhouse study was conducted to evaluate the effects of surface applications of amendments on lead bioavailability in the tailings. Treatments included sediment only, and sediment with three different surface amendments: (i) biosolids compost plus wood ash, (ii) compost + wood ash + a low SO4(2-) addition as K2SO4, and (iii) compost + wood ash + a high SO4(2-) addition. Measured variables included growth and tissue Pb, Zn, and Cd concentration of arrowhead (Sagittaria latifolia Willd.) and cattail (Typha latifolia L.) and soil pH, redox potential (Eh), pore water Pb, Pb speciation by X-ray absorption spectroscopy, and in vitro Pb bioavailability. The compost + ash amendment alleviated phytotoxicity for both plant species. Bioavailability of Pb as measured by a rapid in vitro extract decreased by 24 to 34% (over control) in the tailings directly below the amendment layer in the compost + SO4 treatments. The ratio of acid volatile sulfide (AVS) to simultaneously extracted metals (SEM) also indicated a reduction in Pb bioavailability (1:40 control, 1:20 compost, 1:8 compost + low SO4, and 1:3 compost + high SO4). Extended X-ray adsorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectroscopy data indicated that lead sulfide was greater after 99 d in the treatments that included additions of sulfate. These results indicated that, under reducing conditions, surface amendments of compost + wood ash (with or without sulfate) decreased the bioavailability of Pb in metal-contaminated mine tailings.  相似文献   
120.
Sensitivity analyses for the preferential flow model MACRO were carried out using one-at-a-time and Monte Carlo sampling approaches. Four different scenarios were generated by simulating leaching to depth of two hypothetical pesticides in a sandy loam and a more structured clay loam soil. Sensitivity of the model was assessed using the predictions for accumulated water percolated at a 1-m depth and accumulated pesticide losses in percolation. Results for simulated percolation were similar for the two soils. Predictions of water volumes percolated were found to be only marginally affected by changes in input parameters and the most influential parameter was the water content defining the boundary between micropores and macropores in this dual-porosity model. In contrast, predictions of pesticide losses were found to be dependent on the scenarios considered and to be significantly affected by variations in input parameters. In most scenarios, predictions for pesticide losses by MACRO were most influenced by parameters related to sorption and degradation. Under specific circumstances, pesticide losses can be largely affected by changes in hydrological properties of the soil. Since parameters were varied within ranges that approximated their uncertainty, a first-step assessment of uncertainty for the predictions of pesticide losses was possible. Large uncertainties in the predictions were reported, although these are likely to have been overestimated by considering a large number of input parameters in the exercise. It appears desirable that a probabilistic framework accounting for uncertainty is integrated into the estimation of pesticide exposure for regulatory purposes.  相似文献   
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