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891.
Book reviews     
European Environmental Yearbook

Achille Cutrera, DocTer/Institute for Environmental Studies, Milan (compilers) London, DocTer International, 1991, 897 pp., £60 (plus p. & p.)

House Building in Britain's Countryside

Mark Shucksmith

London, Routledge, 1990, 234 pp., £35  相似文献   

892.
Traditionally, environmental issues and concerns have been viewed as a constraint to businesses. This has resulted in environmental managers relying heavily on a reactive, compliance-based approach to justify change. Businesses are now recognizing that efficient management in the environmental arena can benefit the entire company and open new opportunities for increased profits. Managers have acknowledged that environmental issues can be integrated into daily business trends and activities. Not only does sound environmental management decrease liability, but also in current markets a “green” image can attract investors and customers. This article shows how one tool that progressive companies are focusing attention on—environmental performance indicators—is being used to convey the current status of environmental issues and improve the management of these issues for the benefit of the company as well as the environment.  相似文献   
893.
ABSTRACT Development of community water systems in rural areas through the Farmers Home Administration, U. S. D. A., has been marked since the initiation of the program in the early 1%O's. System development in Mississippi has been very rapid and now numbers the largest among the states excepting Texas. Concurrent with this growth, however, has been a concern for operational quality and efficiency as well as questions of community impacts. The paper is purposed with describing the results of research conducted relative to these areas and methods currently being employed or considered for dealing with problematic items.  相似文献   
894.
ABSTRACT: The 26-mile man-made beach bordering part of Mississippi's Gulf Coast and the contiguous Mississippi Sound waters provide an important recreational and tourist attraction for that area. Being the tourist nucleus for the State, announcements in September 1973 by the Mississippi Air and Water Pollution Control Commission and the State Board of Health that Sound waters had reached a level of pollution that made them potentially dangerous for body contact was met with a myriad of responses. The resulting multi-governmental, multi-agency interface that resulted in trying to deal with the situation highlighted the type of problems that can arise when social, economic, political, and legal forces come to bear on a sensitive area. Questions of jurisdictional and legal authority to act, tourist industry economic pressures, and water quality testing and monitoring procedures were representative of the type of problems that arose during this period. A retrospective analysis of this problem served to isolate the type of articulation that is essential between federal, state, and local agencies vested with responsibilities such as monitoring water quality, protecting public health, etc. This paper develops some of the interface complexities that emerged in dealing with this problem and makes selected recommendations for other areas that may potentially face similar situations.  相似文献   
895.
Runoff water quality improvement from three yard waste compost erosion control treatments were compared with two conventional treatments and an untreated control on plots of 3:1 slope during two growing seasons, using natural events and simulated rainfall. Runoff volume, suspended solids, nutrients, biomass, turf shear strength, and turfgrass color scale were monitored. The most effective compost treatment, a 5-cm thick blown compost blanket, produced 12.7 times less runoff and 9.8 times less sediment load than a straw mat and silt fence treatment. The compost treatments generated eight times more biomass than the straw mat treatments. Root development was significantly better on the compost treatments based on turf shear strength measurements. Tilled-in compost was not as effective as a compost blanket at reducing sediment loss, particularly before the establishment of grass on the plot. The cost of compost treatments was similar to that of straw mat with silt fence treatments.  相似文献   
896.
In certain hydrogeological situations, fluid density variations occur because of changes in the solute or colloidal concentration, temperature, and pressure of the groundwater. These include seawater intrusion, high-level radioactive waste disposal, groundwater contamination, and geothermal energy production. When the density of the invading fluid is greater than that of the ambient one, density-driven free convection can lead to transport of heat and solutes over larger spatial scales and significantly shorter time scales than compared with diffusion alone. Beginning with the work of Lord Rayleigh in 1916, thermal and solute instabilities in homogeneous media have been studied in detail for almost a century. Recently, these theoretical and experimental studies have been applied in the study of groundwater phenomena, where the assumptions of homogeneity and isotropy rarely, if ever, apply. The critical role that heterogeneity plays in the onset as well as the growth and/or decay of convective motion is discussed by way of a review of pertinent literature and numerical simulations performed using a variable-density flow and solute transport numerical code. Different styles of heterogeneity are considered and range from continuously "trending" heterogeneity (sinusoidal and stochastic permeability distributions) to discretely fractured geologic media. Results indicate that both the onset of instabilities and their subsequent growth and decay are intimately related to the structure and variance of the permeability field. While disordered heterogeneity tends to dissipate convection through dispersive mixing, an ordered heterogeneity (e.g., sets of vertical fractures) allows instabilities to propagate at modest combinations of fracture aperture and separation distances. Despite a clearer understanding of the processes that control the onset and propagation of instabilities, resultant plume patterns and their migration rates and pathways do not appear amenable to prediction at present. The classical Rayleigh number used to predict the occurrence of instabilities fails, in most cases, when heterogeneous conditions prevail. The incorporation of key characteristics of the heterogeneous permeability field into relevant stability criteria and numerical models remains a challenge for future research.  相似文献   
897.
Studies on plant-mediated fate of the explosives RDX and HMX   总被引:2,自引:0,他引:2  
The fate of the explosives RDX and HMX on exposure to plants was investigated in 'natural' aquatic systems of Myriophyllum aquaticum for 16 days, and in axenic hairy root cultures of Catharanthus roseus for > or = 9 weeks. Exposure levels were: HMX, 5 mg/l; and RDX, approximately 8 mg/l. Exposure outcomes observed include: HMX, no transformation by aquatic plants, and minimal biological activity by axenic roots; and RDX, removal by both plant systems. In the case of RDX exposure to axenic roots, since 14C-RDX was included, removal was confirmed by the accumulation of 14C-label in the biomass. The intracellular 14C-label in these RDX studies was detected in two forms: intact RDX and bound unknown(s).  相似文献   
898.
899.
Gene flow between populations of the asteroid Linckia laevigata (Linnaeus) was investigated by examining over 1000 individuals collected from ten reefs throughout the Great Barrier Reef (GBR), Australia, for genetic variation at seven polymorphic enzyme loci. Despite geographic separations in excess of 1000 km, Nei's unbiased genetic distance (0 to 0.003) and standardised genetic variation between populations (F ST) values (mean 0.0011) were small and not significant. Genetic homogeneity among L. laevigata populations is consistent with the long-distance dispersal capability of its 28 d planktonic larval phase, and is greater than that observed for other asteroid species, including another high-dispersal species, Acanthaster planci, which has a 14 d larval phase. Variation within populations was also higher than previously recorded for asteroids (mean heterozygosity=0.384; number of alleles per locus ranged from 5.1 to 6.0 in each population). Among asteroids, dispersal ability is positively correlated with gene flow and levels of variation, and negatively correlated with levels of differentiation.  相似文献   
900.
On 25 April 1998, a breach of the tailings dam of the Los Frailes pyrite mine in southwestern Spain resulted in the release of 6 million m3 of acidic water and toxic sludge high in heavy metals. Contaminated material extended 40 km downstream, affecting agricultural land and parts of the wildlife-rich Do?ana Natural and National Parks, including the Entremuros, a very important area for birds. We report on the concentrations, distributions and bioavailability of zinc and cadmium in soil and vegetation from the Entremuros in November 1998 and October 1999, following 2 'cleanup' operations. Levels of Zn and Cd in soil increased significantly over this period, although this was not reflected consistently in metal concentrations in emergent macrophytes. We recommend monitoring of further cleanup attempts in order to develop means of minimizing potential impacts to wildlife in the area.  相似文献   
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