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131.
The Great Lakes Hydrography Dataset: Consistent,Binational Watersheds for the Laurentian Great Lakes Basin
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Danielle K. Forsyth Catherine M. Riseng Kevin E. Wehrly Lacey A. Mason John Gaiot Tom Hollenhorst Craig M. Johnston Conrad Wyrzykowski Gust Annis Chris Castiglione Kent Todd Mike Robertson Dana M. Infante Lizhu Wang James E. McKenna Gary Whelan 《Journal of the American Water Resources Association》2016,52(5):1068-1088
Ecosystem‐based management of the Laurentian Great Lakes, which spans both the United States and Canada, is hampered by the lack of consistent binational watersheds for the entire Basin. Using comparable data sources and consistent methods, we developed spatially equivalent watershed boundaries for the binational extent of the Basin to create the Great Lakes Hydrography Dataset (GLHD). The GLHD consists of 5,589 watersheds for the entire Basin, covering a total area of approximately 547,967 km2, or about twice the 247,003 km2 surface water area of the Great Lakes. The GLHD improves upon existing watershed efforts by delineating watersheds for the entire Basin using consistent methods; enhancing the precision of watershed delineation using recently developed flow direction grids that have been hydrologically enforced and vetted by provincial and federal water resource agencies; and increasing the accuracy of watershed boundaries by enforcing embayments, delineating watersheds on islands, and delineating watersheds for all tributaries draining to connecting channels. In addition, the GLHD is packaged in a publically available geodatabase that includes synthetic stream networks, reach catchments, watershed boundaries, a broad set of attribute data for each tributary, and metadata documenting methodology. The GLHD provides a common set of watersheds and associated hydrography data for the Basin that will enhance binational efforts to protect and restore the Great Lakes. 相似文献
132.
Steve Kelling Daniel Fink Frank A. La Sorte Alison Johnston Nicholas E. Bruns Wesley M. Hochachka 《Ambio》2015,44(4):601-611
Data from well-designed experiments provide the strongest evidence of causation in biodiversity studies. However, for many species the collection of these data is not scalable to the spatial and temporal extents required to understand patterns at the population level. Only data collected from citizen science projects can gather sufficient quantities of data, but data collected from volunteers are inherently noisy and heterogeneous. Here we describe a ‘Big Data’ approach to improve the data quality in eBird, a global citizen science project that gathers bird observations. First, eBird’s data submission design ensures that all data meet high standards of completeness and accuracy. Second, we take a ‘sensor calibration’ approach to measure individual variation in eBird participant’s ability to detect and identify birds. Third, we use species distribution models to fill in data gaps. Finally, we provide examples of novel analyses exploring population-level patterns in bird distributions. 相似文献
133.
Tom Johnston Quentin Chiotti 《Journal of the Air & Waste Management Association (1995)》2013,63(4):563-569
ABSTRACT The assessment of climate change impacts on agriculture has emerged as a recognizable field of research over the past 15 years or so. In a relatively short period, this area of work has undergone a number of important conceptual and methodological developments. Among many questions that have been debated are the adaptability of agriculture to climate change and the importance of land management adjustments in reducing the adverse effects of climate change. In turn, this latter focus has spawned a discussion regarding the nature of adaptation and the ability of agriculture to respond to sudden and rapid climatic changes. In this paper we present an overview of this debate. It is argued that the first generation of climate change impact studies generally ignored the possibility that agriculturalists may adjust their farming practices in order to cope with climate change or to take advantage of new production opportunities. This conceptual oversight has been largely eliminated over the past five years or so. However, questions remain surrounding the likelihood that various adaptive strategies will actually be deployed in particular places. In this paper, we stress the importance of studying adaptation in the context of decision-making at the individual farm level and beyond. 相似文献
134.
Johnston FH Hanigan IC Henderson SB Morgan GG Portner T Williamson GJ Bowman DM 《Journal of the Air & Waste Management Association (1995)》2011,61(4):390-398
Epidemiological studies of exposure to vegetation fire smoke are often limited by the availability of accurate exposure data. This paper describes a systematic framework for retrospectively identifying the cause of air pollution events to facilitate a long, multicenter analysis of the public health effects of vegetation fire smoke pollution in Australia. Pollution events were statistically defined as any day at or above the 95th percentile of the 24-hr average concentration of particulate matter (PM). These were identified for six cities from three distinct ecoclimatic regions of Australia. The dates of each event were then crosschecked against a range of information sources, including online newspaper archives, government and research agency records, satellite imagery, and aerosol optical thickness measures to identify the cause for the excess particulate pollution. Pollution events occurred most frequently during summer for cities in subtropical and arid regions and during winter for cities in temperate regions. A cause for high PM on 67% of days examined in the city of Sydney was found, and 94% of these could be attributed to landscape fire smoke. Results were similar for cities in other subtropical and arid locations. Identification of the cause of pollution events was much lower in colder temperate regions where fire activity is less frequent. Bushfires were the most frequent cause of extreme pollution events in cities located in subtropical and arid regions of Australia. Although identification of pollution episodes was greatly improved by the use of multiple sources of information, satellite imagery was the most useful tool for identifying bushfire smoke pollution events. 相似文献
135.
Roberts DA Johnston EL Poore AG 《Environmental pollution (Barking, Essex : 1987)》2008,156(2):489-503
We determined metal contents of co-occurring algae Padina crassa and Sargassum sp. in Port Jackson (Australia), and relationships between metal levels and the abundance of epifaunal amphipods. Copper, lead and zinc concentrations were amongst the highest yet recorded in these algae. Copper, manganese and lead concentrations were far greater in P. crassa than Sargassum sp., possibly due to the low growth of P. crassa in proximity to contaminated sediments. However, in manipulative experiments the proximity of algae to sediments did not explain these differences. The abundance of herbivorous amphipods correlated negatively with the copper content of P. crassa, but not with the lower concentrations in Sargassum sp. The greater contamination of P. crassa led to patchy distributions of metals in algal beds and recolonisation experiments showed Sargassum sp. acts as a refuge from contaminants for epifauna. The contamination of macroalgae may pose threats to epifauna in harbours around the world. 相似文献
136.
Concentrations of phthalate esters and identification of other additives in PVC children’s toys 总被引:1,自引:0,他引:1
Ruth Stringer Iryna Labunska David Santillo Paul Johnston John Siddorn Angela Stephenson 《Environmental science and pollution research international》2000,7(1):27-36
This study was intended to provide data on the composition of soft PVC toys, addressing the widest practicable range of chemical
additives and including non-phthalate additives. The study also included toys from as many countries as possible, since for
many, no data were available. A total of 72 toys were purchased in 17 countries. The majority (64) were PVC or had PVC sections.
In almost all the soft PVC toys analysed, phthalates comprised a sizeable proportion (most frequently 10–40%) of the total
weight of the toy.
The predominant phthalates detected were diisononyl phthalate (DINP) and di(2-ethylhexyl) phthalate (DEHP). Other phthalates
identified in high concentrations in some toys include isomeric mixes of diisooctyl phthalate (DIOP) and diisodecyl phthalate
(DIDP). The estrogenic chemical nonylphenol was isolated from 13 toys, while 2 toys were found to contain the fungicide Fungitrol
11 (Folpet). 78% of PVC toys contained one or more extractable organic compounds in addition to those reported above.
Some of these data have been released previously by Greenpeace and made available on the internet.This report, however, which
is intended for a technically expert audience, has been peer reviewed and contains further analytical data that have not been
published before. 相似文献
137.
Langan Simon Hodson Mark Bain Derek Hornung Mike Reynolds Brian Hall Jane Johnston Lynne 《Water, Air, & Soil Pollution: Focus》2001,1(1-2):299-312
Current legislation within Europe aimed at limitingecosystem damage resulting from inputs of atmosphericpollution is based on the critical load concept. Mineralweathering rates are central to the calculation ofcritical loads (acceptable levels) of acid deposition.The authors have undertaken a number of studies whichillustrate the complications and limitations inherent inpredicting mineral weathering rates and the implicationswhich these have for critical loads calculations andmapping. Calculated weathering rates and critical loadsfor two acid-sensitive parent materials (greywackes andgranites) are presented and are used to illustrate theimpact that uncertainty can have on critical loadexceedances. The results have obvious implications forportraying the uncertainties of critical loads to policy makers. 相似文献
138.
Plant species composition and community structure were compared among four sites in an upland black spruce community in northwestern Ontario. One site had remained undisturbed since the 1930s and three had been disturbed by either logging, fire, or both logging and fire. Canonical correspondence ordination analyses indicated that herbaceous species composition and abundance differed among the disturbance types while differences in the shrub and tree strata were less pronounced. In the herb stratum Pleurozium schreberi, Ptilium crista-castrensis and Dicranum polysetum were in greatest abundance on the undisturbed forest site, while the wildfire and burned cutover sites were dominated by Epilobium angustifolium and Polytrichum juniperinum. The unburned harvested site was dominated by Epilobium angustifolium, Cornus canadensis and Pleurozium schreberi. Species richness was lower on the undisturbed site than on any of the disturbed sites while species diversity (H) and evenness (Hill's E5) were higher on the unburned harvested site than on the other sites. Results suggest that herb re-establishment is different among harvested and burned sites in upland black spruce communities and we hypothesize that differences in the characteristics of the disturbance were responsible, in particular, the impact of burning on nutrient availability. These differences need to be taken into account in determining the effects of these disturbances on biodiversity and long-term ecosystem management. 相似文献
139.
Habitat-forming organisms often determine the structural properties and food resources available to a wide diversity of associated
mobile species. Sessile invertebrate assemblages on marine hard substrates support an abundant fauna of mobile invertebrates
whose associations with traits of their host assemblages are poorly known. To assess how changes to habitat-forming species
are likely to affect their associated mobile fauna, the relationships between abundance, diversity and composition of mobile
invertebrates and the diversity, cover and composition of the sessile assemblages they use as habitat were quantified in Sydney
Harbour, Australia (33°50′S, 151°16′E). Similar compositions of sessile species were more likely to share a similar composition
of mobile species, but univariate measures of the habitat (percent cover, species and functional diversity, prevalence of
non-indigenous species) did not predict variation in associated mobile assemblages. These results demonstrate that in this
habitat it is difficult to predict the diversity of marine assemblages based on common surrogate measures of biodiversity. 相似文献
140.
When animals die in traps in a mark-recapture study, straightforward likelihood inferences are possible in a class of models.
The class includes M0, Mt, and Mb as reported by White et al. (Los Alamos National Laboratory, LA-8787-NERP, pp 235, 1982), those that do not involve heterogeneity.
We include three Markov chain “persistence” models and show that they provide good fits in a trapping study of deer mice in
the Cascade-Siskiyou National Monument of Southern Oregon where trapping mortality was high.
相似文献
Fred L. RamseyEmail: |