全文获取类型
收费全文 | 51篇 |
免费 | 0篇 |
专业分类
废物处理 | 2篇 |
环保管理 | 20篇 |
综合类 | 3篇 |
基础理论 | 5篇 |
污染及防治 | 16篇 |
评价与监测 | 4篇 |
社会与环境 | 1篇 |
出版年
2021年 | 1篇 |
2013年 | 5篇 |
2011年 | 3篇 |
2010年 | 4篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有51条查询结果,搜索用时 15 毫秒
21.
Claire Brussol Matthew Duane Patrick Carlier Dimitrios Kotzias 《Environmental science and pollution research international》1999,6(3):138-140
The photo-induced degradation of naphthalene, 1,4-naphthoquinone, 1-naphthol and 1-NO2 naphthalene, adsorbed on silica gel, and with the addition of nitrogenous air pollutants e.g. NO2 (as KNO2) was investigated. Results indicate that compounds adsorbed onto a solid carrier are degraded when irradiated with UV light
(λ > 290 nm) in the presence of nitrites. The key species initiating the naphthalene degradation is the OH-radical which is
generated through the photolysis of NO2. Reaction products identified were 2-formyl-cinnamaldehyde, 1,4-naphthoquinone, nitronaphthol, o-phthaldialdehyde, phthalide
and nitronaphthalene. A mass balance between 40–50% was achieved. Under the same irradiation conditions, 1-NO2 naphthalene is mainly degraded by direct photolysis while degradation of 1-naphthol and 1,4-naphthoquinone proceeds via the
reaction with OH-radicals. Identified products were hydroxy-nitro-nitroso- and quinones compounds. 相似文献
22.
Efforts to Reduce Mortality to Hydroelectric Turbine-Passed Fish: Locating and Quantifying Damaging Shear Stresses 总被引:1,自引:0,他引:1
Severe fluid forces are believed to be a source of injury and mortality to fish that pass through hydroelectric turbines.
A process is described by which laboratory bioassays, computational fluid dynamics models, and field studies can be integrated
to evaluate the significance of fluid shear stresses that occur in a turbine. Areas containing potentially lethal shear stresses
were identified near the stay vanes and wicket gates, runner, and in the draft tube of a large Kaplan turbine. However, under
typical operating conditions, computational models estimated that these dangerous areas comprise less than 2% of the flow
path through the modeled turbine. The predicted volumes of the damaging shear stress zones did not correlate well with observed
fish mortality at a field installation of this turbine, which ranged from less than 1% to nearly 12%. Possible reasons for
the poor correlation are discussed. Computational modeling is necessary to develop an understanding of the role of particular
fish injury mechanisms, to compare their effects with those of other sources of injury, and to minimize the trial and error
previously needed to mitigate those effects. The process we describe is being used to modify the design of hydroelectric
turbines to improve fish passage survival. 相似文献
23.
P. Lammers 《Die Naturwissenschaften》1964,51(23):552-553
24.
Polycyclic aromatic hydrocarbons (PAHs) are considered to act additively when exposed as congener mixtures. Additive internal concentrations at the site of toxic action is the basis for recent efforts to establish a sum PAH guideline for sediment-associated PAH toxicity. This study determined the toxicity of several PAH congeners on a body residue basis in Diporeia spp. These values were compared to the previously established LR(50) value for a PAH mixture based on the molar sum of PAH congeners and demonstrated similar LR(50) values for individual PAH. These results support the contention that the PAH act at the same molar concentration whether present as individual compounds or in mixture. Aqueous exposures were conducted for 28 d, and the water was exchanged daily to maintain the exposure concentration. The concentration in the exposures declined by an average of 22% between water exchanges across all compounds, and ranged from 11% to 32%. The toxicokinetics were determined using both time-weighted-average (TWA) and time-variable water concentrations and were not statistically different between the two source functions. Toxicity was determined for both mortality and immobility (failure to swim on prodding) and on both a TWA water concentration and a body residue basis. The LC(50) values ranged from 1757 microg l(-1) for naphthalene after 10 d exposure to 79.1 microg l(-1) for pyrene after 28 d exposure, and the EC(50) ranged from 1587 microg l(-1) for naphthalene after 10 d exposure to 38.2 microg l(-1) for pyrene after 28 d exposure. The LR(50) values for all congeners at all lengths of exposure were essentially constant and averaged 7.5+/-2.6 micromol g(-1), while the ER(50) for immobility averaged 2.6+/-0.6 micromol g(-1). The bioconcentration factor declined with increasing exposure concentration and was driven primarily by a lower uptake rate with increasing dose, while the elimination remained essentially constant for each compound. 相似文献
25.
William T. Lammers 《Environment international》1979,2(3):127-131
Over the past 15 years this laboratory has used three methods to isolate virus and virus-like particles from natural water. Enough data have been gained to compare the results. Virus and virus-like particles are organic colloids, and in natural water this class generally requires some from of concentration from their water phase. Direct concentration by continuous-flow centrifugation has the capacity for processing samples of 100 1 or more. Thus, extremely rare particles may be concentrated to quantities sufficient for analyses. This method is non-discriminatory, collecting essentially all particles which fall within the range of the centrifugal impulse. If a continuous sampler is desired, one may use biological pre-concentrators such as filter feeding bivalves, or grazing aquatic gastropods, and extract the colloids the feeding habits of these molluscs concentrate from the water. Density gradient centrifugation can separate the colloids concentrated by any of the above methods into relatively uniform groups based on buoyant density and sedimentation coefficient. Biological, physical, and chemical analyses then allow culture and further identification of the isolates. 相似文献
26.
27.
Ruscena Wiederholt Eduardo Fernandez-Duque Duane R. Diefenbach 《Ecological modelling》2010,221(20):2482-2490
Overexploitation of wildlife populations occurs across the humid tropics and is a significant threat to the long-term survival of large-bodied primates. To investigate the impacts of hunting on primates and ways to mitigate them, we developed a spatially explicit, individual-based model for a landscape that included hunted and un-hunted areas. We used the large-bodied neotropical red howler monkey (Alouatta seniculus) as our case study species because its life history characteristics make it vulnerable to hunting. We modeled the influence of different rates of harvest and proportions of landscape dedicated to un-hunted reserves on population persistence, population size, social dynamics, and hunting yields of red howler monkeys. In most scenarios, the un-hunted populations maintained a constant density regardless of hunting pressure elsewhere, and allowed the overall population to persist. Therefore, the overall population was quite resilient to extinction; only in scenarios without any un-hunted areas did the population go extinct. However, the total and hunted populations did experience large declines over 100 years under moderate and high hunting pressure. In addition, when reserve area decreased, population losses and losses per unit area increased disproportionately. Furthermore, hunting disrupted the social structure of troops. The number of male turnovers and infanticides increased in hunted populations, while birth rates decreased and exacerbated population losses due to hunting. Finally, our results indicated that when more than 55% of the landscape was harvested at high (30%) rates, hunting yields, as measured by kilograms of biomass, were less than those obtained from moderate harvest rates. Additionally, hunting yields, expressed as the number of individuals hunted/year/km2, increased in proximity to un-hunted areas, and suggested that dispersal from un-hunted areas may have contributed to hunting sustainability. These results indicate that un-hunted areas serve to enhance hunting yields, population size, and population persistence in hunted landscapes. Therefore, spatial regulation of hunting via a reserve system may be an effective management strategy for sustainable hunting, and we recommend it because it may also be more feasible to implement than harvest quotas or restrictions on season length. 相似文献
28.
F Jay Breidt Duane C. Roes Joel I. Wagner Mark D. Flora 《Journal of the American Water Resources Association》1991,27(4):593-602
ABSTRACT: Existing water quality for the Middle Delaware Scenic and Recreational River is significantly better than is required by current standards, leaving a potential for degradation. A method is presented for deriving candidate antidegradation water quality criteria for this segment of the Delaware River using statistical analysis of historic (ambient) water quality data. Data for 34 water quality parameters are first evaluated for data density, serial correlation, trend, seasonality, and other factors. These preliminary analyses are based on observation of data plots and application of distribution-free statistical techniques that are insensitive to outliers and are robust to relatively mild violations of basic assumptions. Data for 12 of the parameters have sufficient density for further analysis and can reasonably be modeled as independent and identically distributed over time (either seasonally or for the entire data sets). For these 12 parameters, distribution-free statistical methods are developed and used to derive intervals within which there is high confidence (usually greater than 95 percent) that the quantiles with potential use as anti-degradation criteria (the 0.85th, 0.90th, and 0.95th quantiles in this study) for a particular parameter lie. 相似文献
29.
ABSTRACT: The Yellowstone River in Montana produces an abundant supply of high quality water, but in the early 1970's, the specter of mushrooming energy development in the drainage with its attendant demands for large volumes of water prompted this state to initiate steps to protect existing users and to control future water uses. A Water Use Act was passed in 1973, and a moratorium was subsequently placed on the granting of new permits for major diversion. During this moratorium, various governmental entities were given the opportunity to request the reservation of water for future beneficial uses, including instream purposes. An earlier paper described the reservation applications that were received by the state, and it also summarized the legal framework of the reservation process in Montana. Since that time, the responsible state agency has had the opportunity to review the reservation requests, and its final decision in this regard was announced in December of 1978. This paper describes the details of this decision. Basically, an attempt was made to preserve the integrity of the stream while also strengthening its agricultural uses. In addition, a portion of the flow was not earmarked which will provide some flexibility in reacting to future demands. 相似文献
30.
Duane C. Wollmuth John H. Schomaker Lawrence C. Merriam 《Journal of the American Water Resources Association》1985,21(5):851-857
The Recreation Opportunity Spectrum (ROS) system is used by the USDA Forest Service and USDI Bureau of Land Management for inventorying, classifying, and managing wildlands for recreation. Different ROS classes from the Colorado and Arkansas Rivers in Colorado were compared, using visitor survey data collected in 1979 and 1981, to see if the different classes offered different recreational experience opportunities. No difference between classes was found. Six possible reasons for not finding a difference are discussed. The usefulness of ROS at the broader levels of planning and the needs at more detailed levels of planning are noted. 相似文献