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101.
Enrique V. Palacios John C. Day 《Journal of the American Water Resources Association》1977,13(4):709-720
ABSTRACT: In this paper a new methodology for estimating conveyance efficiency within irrigation systems is presented. Based on statistical analysis of daily water releases from the source of supply and deliveries to the farmers in an irrigation district in Mexico, a linear model is obtained for estimating conveyance efficiency and two component factors. One of these factors points out the relative importance of the operational losses (i.e., losses due to water management), and the second shows the importance of the fixed losses which can be attributed to the average flow through the canal network without variations. In the last part of this paper, an analysis of the expected benefits and costs accruing from system improvement permits derivation of a decision rule which may be used for analyzing the economic feasibility of lining in-place canals. 相似文献
102.
Taxodium distichum (L.) Rich.]. The study site, a swamp in St. Martin Parish, Louisiana, has received municipal wastewater for the last 40 years.
Growth chronologies from 1920 to 1992 were developed from cross-dated tree core samples taken from treated and control sites
with similar size and age classes. Mean diameter increment (DINC) and mean basal area increment (BAI) chronologies were constructed
separately for each stand. These chronologies were then summarized by tree and stand into seven nine-year intervals resulting
in three pretreatment intervals from 1926 to 1952 and four treatment intervals from 1953 to 1988. Significant differences
in growth response between sites showed a consistent pattern of growth enhancement in the treated site coincident with the
onset of effluent discharge. The ratio of treated to control baldcypress growth rates (computed from DINC) averaged 0.74 during
the pretreatment period and 1.53 during the treatment period. Over the period of study, control DINC decreased from 77 mm
to 29 mm/nine-year interval, while treatment DINC increased slightly from 40 mm to 47 mm/nine-year interval. Control BAI did
not increase significantly and averaged 192 cm2/nine-year interval. There was a significant increase in treatment BAI from 129 to 333 cm2/nine-year interval over the period of record. These results clearly demonstrate sustained long-term baldcypress growth enhancement
throughout 40 years of municipal effluent discharge. 相似文献
103.
Experiments were conducted on the Black Mesa Coal Mine, Kayenta, Arizona in 1977 and 1978 to study the effectiveness of Hold-Gro
Erosion Control Fabric (a product from the Gulf States Paper Corporation, Tuscaloosa, Alabama) in the establishment of plants
on coal mine soil following the surface mining of coal. Four plant species were planted: (1) spring barley (Horduem vulgare L.), an annual grass (2) crested wheatgrass (Agropyron cristatum L.), a perennial grass (3) alfalfa (lucerne) (Medicago sativa L.), a perennial legume and (4) fourwing saltbush (Atriplex canescens Pursh.), a perennial shrub. Seeds of each plant species were planted in reclaimed coal mine soil in the spring of the year
by both broadcast seeding (conventional culture) and the incorporation of seeds in Hold-Gro Erosion Control Fabric. Average
numbers of seedlings established and percent ground cover for all species studied were higher in areas where conventional
culture was used than they were in areas where seeds were incorporated in Hold-Gro Erosion Control Fabric. The incorporation
of seeds in Hold-Gro Erosion Control Fabric in the establishment of plant species on coal mine soil was not an effective cultural
practice in the southwestern United States.
The authors gratefully acknowledge the assistance of M.A. Norem with portions of the research involving this contribution.
The authors also express their appreciation to the Gulf States Paper Corporation in Tuscaloosa. Alabama for providing the
Hold-Gro Erosion Control Fabrie used in this research.
Contribution from the Arizona Agr. Exp. Stn., University of Arizona, Tucson, Arizona 85721. Approved for publication as Arizona
Agr. Exp. Stn. Research Contribution No. 3767. 相似文献
104.
A two-year experiment was conducted on the Black Mesa Coal Mine near Kayenta, Arizona to investigate the growth and establishment of seven plant species in unmined soil (undisturbed soil) and coal-mine soil (spoils). Natural rainfall (20 cm/yr) and natural rainfull plus sprinkler irrigation (50 cm/yr) were the irrigation treatments applied to each soil material. Plant species grew better in unmined soil than in coal-mine soil. Supplemental irrigation water resulted in more plant growth than did natural rainfall alone in both soil materials; however, there were highly significant differences among species. Alfalfa (Medicago sativa L.) and all of the annual perennial grasses used, excluding Indian ricegrass (Oryzopsis hymenoides Ricker), produced effective ground cover on both soil materials when they received supplemental irrigation water. Fourwing saltbush (Atriplex canescens Pursh.) had low germination (emergence), seedling establishment, and stem production during the first year of growth; however, in the second year of growth, this species produced a dense ground cover on coal-mine soil with natural rainfall plus irrigation. In revegetating the Black Mesa Coal Mine, Harlan II barley (Hordeum vulgare L.) and Super X wheat (Triticum aestivum L.) provided initial protective cover until adapted perennial species could be established for permanent stabilisation. The Black Mesa Research Study indicated that irrigation water during seedling establishment was essential for the effective stabilisation of coal-mine soils in a semiarid environment. 相似文献
105.
Diana G. Day 《The Environmentalist》1991,11(1):9-17
Summary Australia's first National Environment Statement focuses on the substantial ecologic and economic impacts of land degradation, primarily in the significant agricultural mega-region of the Murray-Darling Basin. But the Statement only summarises existing policies to show a A$500 million spending programme on the environment. Inescapable, is the conclusion that economic growth as present and projected, and environmental sustainability, cannot co-exist in the long term. Levels of awareness of Australia's diverse environmental concerns were measured but no targets or future achievements were chartered — so how is effective management to be attained? The proposed significant and rapid devolution of power for action to local government, catchment management groups and community associations is a welcome development but this must be supported by adequate technical information and guidance by government.Dr Diana G. Day is an environmental policy analyst with major interests in water planning. She is currently setting up a new Centre for Environmental Management at Newcastle University, and is Director of the National Land and Water Resources Research and Development Corporation in Australia. 相似文献
106.
Sue Markland Day 《补救:环境净化治理成本、技术与工艺杂志》1992,2(3):249-258
Remediation of refinery wastes is regulated by three major federal environmental statutes: the Clean Air Act, the Clean Water Act, and the Resource Conservation and Recovery Act (RCRA); other statutes apply, but to a lesser degree. During the past two years, RCRA's rules have effectively outlawed the passive biological treatment of primary refinery waste sludges in waste ponds and lagoons, even though the law recommends active biological treatment as the second stage in the waste treatment train. RCRA's land disposal restrictions may also outlaw land farming treatment for the bottom sludges involved in crude oil storage. Since 1980, when the U.S. Environmental Protection Agency listed an initial group of five waste streams as hazardous, the agency has listed two more waste streams and twenty-five organic constituents, several found in petroleum wastes. Now it is about to list fourteen more petroleum refining wastes and is studying the addition of fifteen more waste streams. Treatment standards and restrictions have also been promulgated. This article explores the biotreatment techniques and technologies that are still available to petroleum and environmental engineers. 相似文献
107.
Nancy S. Day Marija Tadin Angela M. Christiano Patricia Lanzano Sergio Piomelli Stephen Brown 《黑龙江环境通报》2002,22(8):686-691
Prenatal diagnosis of sickle cell diseases has been available for several years, and our laboratory has performed over 1000 prenatal diagnoses. However, currently available techniques are labor-intensive and time-consuming, and thus the diagnosis is delayed, making the mother's decision difficult. We describe a rapid, high-throughput technique based on the ligation assay coupled with automated capillary fluorescence detection. This new approach allows the diagnosis of both Hgb S and Hgb C to be available in a few hours. We have utilized this technique in 30 prenatal diagnoses and found it to be in complete agreement with the standard diagnoses. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
108.
Energy analysis of nonmarket values of the Mississippi Delta 总被引:1,自引:0,他引:1
An energy analysis was used to estimate nonmarket values under various land cover scenarios in the Mississippi Delta. Land
loss since 1900 has led to a decline in nonmarket values from $3.1 billion/year in 1900 to $2.5 billion in 1990, resulting
in a total loss of $29.4 billion. This loss is concentrated in the Barataria-Terrebonne basins, where nonmarket value has
dropped from $1.6 billion/year in 1956 to $1.3 billion/year in 1988. Although values are projected to increase in the Atchafalaya
basin (from $723 million/year in 1988 to $756 million/year in 2058), total nonmarket value for the Louisiana coast is projected
to decrease to $2.1 billion/year under currently approved levels of restoration. 相似文献
109.