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71.
The Leaching Characteristics of Chromite ore Processing Residue 总被引:1,自引:0,他引:1
D. Deakin L.J. West D.I. Stewart B.W.D. Yardley 《Environmental geochemistry and health》2001,23(3):201-206
72.
Wagner T Bremigan MT Cheruvelil KS Soranno PA Nate NA Breck JE 《Environmental monitoring and assessment》2007,130(1-3):437-454
The ecoregion and watershed frameworks are landscape-based classifications that have been used to group waterbodies with respect to measures of community structure; however, they have yet to be evaluated for grouping lakes for demographic characteristics of fish populations. We used a multilevel modeling approach to determine if variability in mean fish length at age could be partitioned by ecoregions and watersheds. For the ecoregions analysis, we then examined if within-ecoregion variability could be explained by local water quality and lake morphometry characteristics. We used data from agency surveys conducted during 1974-1984 for age 2 and 3 fish of seven common warm and coolwater fish species. Variance in mean length at age between ecoregions for all species was not significant, and between-watershed variance estimates were only significant in 3 out of 14 analyses; however, the total amount of variation between watersheds was very small (ranging from 1.8% to 3.7% of the total variance), indicating that ecoregions and watersheds were ineffective in partitioning variability in mean length at age. Within ecoregions, water quality and lake morphometric characteristics accounted for 2%-23% of the variation in mean length at age. Measures of lake productivity were the most common significant covariates, with mean length at age increasing with increasing lake productivity. Much of the variability in mean length at age was not accounted for, suggesting that other local factors such as biotic interactions, fish density, and exploitation are important. The results indicate that the development of an effective regional framework for managing inland lakes will require a substantial effort to understand sources of demographic variability and that managers should not rely solely on ecoregions or watersheds for grouping lakes with similar growth rates. 相似文献
73.
Cohen et al. [16] suggest that in order to explore ways to bring climate change (CC) and sustainable development (SD) research together, it is necessary to develop more heuristic tools that can involve resource users and other stakeholders. In this respect, this paper focuses on methodological development in research to study climate change impacts and regional sustainable development (RSD). It starts with an introduction of an integrated land assessment framework (ILAF) which is part of the integrated phase of the Mackenzie Basin Impact Study (MBIS) in Canada. The paper then provides some articulation on how the integrated approach was applied in the Mackenzie Basin to show implications of climate change for RSD. 相似文献
74.
Particle-reactive, naturally occurring radionuclides are useful tracers of the sinking flux of organic matter from the surface to the deep ocean. Since the Joint Global Ocean Flux Study (JGOFS) began in 1987, the disequilibrium between 234Th and its parent 238U has become widely used as a technique to measure particle export fluxes from surface ocean waters. Another radionuclide pair, 210Po and 210Pb, can be used for the same purpose but has not been as widely adopted due to difficulty with accurately constraining the 210Po/210Pb radiochemical balance in the ocean and because of the more time-consuming radiochemical procedures. Direct comparison of particle flux estimated in different ocean regions using these short-lived radionuclides is important in evaluating their utility and accuracy as tracers of particle flux. In this paper, we present paired 234Th/238U and 210Po/210Pb data from oligotrophic surface waters of the subtropical Northwest Atlantic and discuss their advantages and limitations. Vertical profiles of total and particle size-fractionated 210Po and 234Th activities, together with particulate organic carbon (POC) concentrations, were measured during three seasons at the Bermuda Atlantic Time-series Study (BATS) site. Both 210Po and 234Th reasonably predict sinking POC flux caught in sediment traps, and each tracer provides unique information about the magnitude and efficiency of the ocean's biological pump. 相似文献
75.
Lizhu Wang Kevin Wehrly James E. Breck Lidia Szabo Kraft 《Environmental management》2010,46(3):471-483
Assessment of lake impairment status and identification of threats’ type and source is essential for protection of intact,
enhancement of modified, and restoration of impaired lakes. For regions in which large numbers of lakes occur, such assessment
has usually been done for only small fractions of lakes due to resource and time limitation. This study describes a process
for assessing lake impairment status and identifying which human disturbances have the greatest impact on each lake for all
lakes that are 2 ha or larger in the state of Michigan using readily available, georeferenced natural and human disturbance
databases. In-lake indicators of impairment are available for only a small subset of lakes in Michigan. Using statistical
relationships between the in-lake indicators and landscape natural and human-induced measures from the subset lakes, we assessed
the likely human impairment condition of lakes for which in-lake indicator data were unavailable using landscape natural and
human disturbance measures. Approximately 92% of lakes in Michigan were identified as being least to marginally impacted and
about 8% were moderately to heavily impacted by landscape human disturbances. Among lakes that were heavily impacted, more
inline lakes (92%) were impacted by human disturbances than disconnected (6%) or headwater lakes (2%). More small lakes were
impacted than medium to large lakes. For inline lakes, 90% of the heavily impacted lakes were less than 40 ha, 10% were between
40 and 405 ha, and 1% was greater than 405 ha. For disconnected and headwater lakes, all of the heavily impacted lakes were
less than 40 ha. Among the anthropogenic disturbances that contributed the most to lake disturbance index scores, nutrient
yields and farm animal density affected the highest number of lakes, agricultural land use affected a moderate number of lakes,
and point-source pollution and road measures affected least number of lakes. Our process for assessing lake condition represents
a significant advantage over other routinely used methods. It permits the evaluation of lake condition across large regions
and yields an overall disturbance index that is a physicochemical and biological indicator weighted sum of multiple disturbance
factors. The robustness of our approach can be improved with increased availability of high-resolution disturbance datasets. 相似文献
76.
Hong S. Moon Jason M. Abercrombie Albert P. Kausch C. Neal Stewart Jr. 《Environmental management》2010,46(4):531-538
Done correctly, cellulosic bioenergy should be both environmentally and economically beneficial. Carbon sequestration and
decreased fossil fuel use are both worthy goals in developing next-generation biofuels. We believe that biotechnology will
be needed to significantly improve yield and digestibility of dedicated perennial herbaceous biomass feedstocks, such as switchgrass
and Miscanthus, which are native to the US and China, respectively. This Forum discusses the sustainability of herbaceous feedstocks relative
to the regulation of biotechnology with regards to likely genetically engineered traits. The Forum focuses on two prominent
countries wishing to develop their bioeconomies: the US and China. These two countries also share a political desire and regulatory
frameworks to enable the commercialization and wide release of transgenic feedstocks with appropriate and safe new genetics.
In recent years, regulators in both countries perform regular inspections of transgenic field releases and seriously consider
compliance issues, even though the US framework is considered to be more mature and stringent. Transgene flow continues to
be a pertinent environmental and regulatory issue with regards to transgenic plants. This concern is largely driven by consumer
issues and ecological uncertainties. Regulators are concerned about large-scale releases of transgenic crops that have sexually
compatible crops or wild relatives that can stably harbor transgenes via hybridization and introgression. Therefore, prior
to the commercialization or extensive field testing of transgenic bioenergy feedstocks, we recommend that mechanisms that
ensure biocontainment of transgenes be instituted, especially for perennial grasses. A cautionary case study will be presented
in which a plant’s biology and ecology conspired against regulatory constraints in a non-biomass crop perennial grass (creeping
bentgrass, Agrostis stolonifera), in which biocontainment was not attained. Appropriate technologies that could be applied to perennial grass feedstocks
for biocontainment are discussed. 相似文献
77.
Pelleted organo-mineral fertilisers from composted pig slurry solids, animal wastes and spent mushroom compost for amenity grasslands 总被引:1,自引:0,他引:1
Rao JR Watabe M Stewart TA Millar BC Moore JE 《Waste management (New York, N.Y.)》2007,27(9):1117-1128
In Ireland, conversion of biodegradable farm wastes such as pig manure spent mushroom compost and poultry litter wastes to pelletised fertilisers is a desirable option for farmers. In this paper, results obtained from the composting of pig waste solids (20% w/w) blended with other locally available biodegradable wastes comprising poultry litter (26% w/w), spent mushroom compost (26% w/w), cocoa husks (18% w/w) and moistened shredded paper (10% w/w) are presented. The resulting 6-mo old 'mature' composts had a nutrient content of 2.3% total N, 1.6% P and 3.1% K, too 'low' for direct use as an agricultural fertiliser. Formulations incorporating dried blood or feather meal amendments enriched the organic N-content, reduced the moisture in mature compost mixtures and aided the granulation process. Inclusion of mineral supplements viz., sulphate of ammonia, rock phosphate and sulphate of potash, yielded slow release fertilisers with nutrient N:P:K ratios of 10:3:6 and 3:5:10 that were suited for amenity grasslands such as golf courses for spring or summer application and autumn dressing, respectively. Rigorous microbiological tests carried out throughout the composting, processing and pelletising phases indicated that the formulated organo-mineral fertilisers were free of vegetative bacterial pathogens. 相似文献
78.
Holly H. Bennett Michael W. Mullen Paul M. Stewart James A. Sawyer E. Cliff Webber 《Journal of the American Water Resources Association》2004,40(1):43-51
ABSTRACT: Activities such as agriculture, silviculture, and mining contribute nonpoint pollution to Alabama's streams through polluted runoff and excessive sedimentation. Highly erodible soils characteristic of the Choctawhatchee‐Pea Rivers watershed, combined with intense rainfall and land use practices, contribute large amounts of sediment to streams. Biological monitoring can reflect the acute impacts of pollutants as well as prolonged effects of habitat alteration, and development of biological criteria is important for the establishment of enforceable laws regarding nonpoint source pollution. Macroinvertebrates were collected from 49 randomly selected sites from first through sixth‐order streams in the Choctawhatchee‐Pea Rivers watershed and were identified to genus level. Thirty‐eight candidate metrics were examined, and an invertebrate community index (ICI) was calibrated by eliminating metrics that failed to separate impaired from unimpaired streams. Each site was scored with those metrics, and narrative scores were assigned based on ICI scores. Least impacted sites scored significantly lower than sites impacted by row crop agriculture, cattle, and urban land uses. Conditions in the watershed suggest that the entire area has experienced degradation through past and current land use practices. An initial validation of the index was performed and is described. Additional evaluations of the index are in progress. 相似文献
79.
Why do people get involved in the creation of new ventures? Prior research suggests entrepreneurial behavior has multiple causes. Nurture explanations; often couched in terms of sociological theories like social learning have been popular. Aspects of nascent entrepreneurs' social contexts, notably their family business background, have been associated with new venture creation. But nature also appears to play a role. Other research has linked heritable biological factors, including testosterone, with the career choice to launch a new venture. This study presents theory and evidence linking the combination of both sociological and biological factors with new venture creation: a biosocial model of entrepreneurship. Empirical results indicate new venture creation is more likely among those individuals having a higher testosterone level in combination with a family business background. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
80.