全文获取类型
收费全文 | 58篇 |
免费 | 4篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 1篇 |
环保管理 | 20篇 |
综合类 | 6篇 |
基础理论 | 17篇 |
污染及防治 | 7篇 |
评价与监测 | 5篇 |
社会与环境 | 4篇 |
灾害及防治 | 3篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2019年 | 1篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2013年 | 1篇 |
2012年 | 2篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有64条查询结果,搜索用时 15 毫秒
61.
Jonathan Ready Kristin Kaschner Paul D. Eastwood Josephine Rius Sven Kullander 《Ecological modelling》2010,221(3):467-478
We present and evaluate AquaMaps, a presence-only species distribution modelling system that allows the incorporation of expert knowledge about habitat usage and was designed for maximum output of standardized species range maps at the global scale. In the marine environment there is a significant challenge to the production of range maps due to large biases in the amount and location of occurrence data for most species. AquaMaps is compared with traditional presence-only species distribution modelling methods to determine the quality of outputs under equivalently automated conditions. The effect of the inclusion of expert knowledge to AquaMaps is also investigated. Model outputs were tested internally, through data partitioning, and externally against independent survey data to determine the ability of models to predict presence versus absence. Models were also tested externally by assessing correlation with independent survey estimates of relative species abundance. AquaMaps outputs compare well to the existing methods tested, and inclusion of expert knowledge results in a general improvement in model outputs. The transparency, speed and adaptability of the AquaMaps system, as well as the existing online framework which allows expert review to compensate for sampling biases and thus improve model predictions are proposed as additional benefits for public and research use alike. 相似文献
62.
Assessment of groundwater quality by means of self-organizing maps: application in a semiarid area 总被引:1,自引:0,他引:1
Sanchez-Martos F Aguilera PA Garrido-Frenich A Torres JA Pulido-Bosch A 《Environmental management》2002,30(5):0716-0726
The Kohonen neural network was applied to hydrochemical data from the Detritic Aquifer of the Lower Andarax, situated in a
semiarid zone in the southeast of Spain. An activation map was obtained for each of the sampling points, in which the spatial
distribution of the activated neurons indicated different water qualities. To extract the information contained in the activation
maps, they were divided into nine quadrats. Cartesian coordinates were assigned to each quadrant (x, y), and for each sampling point, three derived variables were selected, which were assigned the values x and y of the corresponding quadrat. A classification was defined based on this simple matrix system which allows an easy and rapid
means of evaluating the water quality. This assessment highlights the various processes that affect groundwater quality. The
method generates output that is easier to interpret than from traditional statistical methods. The information is extracted
from the activation maps without significant loss of information. The method is proposed for assessing water quality in hydrogeochemically
complex areas, where large numbers of observations are made. 相似文献
63.
Glen D. Johnson Wayne L. Myers Ganapati P. Patil Charles Taillie 《Environmental and Ecological Statistics》2001,8(1):5-20
When a natural landscape is represented by a series of categorical raster maps of varying resolution, a multiresolution characterization of spatial pattern can be obtained in which entropy is computed at each resolution conditional on the next coarser resolution. The series of entropy values is plotted as a function of resolution, resulting in a multiresolution profile of fragmentation pattern in the landscape. If a categorical raster map is available at a single resolution only, a series of degraded maps at increasingly coarser resolutions is generated and the fragmentation profile is computed for this series. An algorithm has been developed for obtaining the profile directly from the single resolution map without having to generate and store the coarser resolution maps. A hierarchical stochastic model is described for simulating categorical raster maps and the fragmentation profile of the generating process is obtained in terms of the model parameters. These process profiles provide benchmarks for assessing empirical profiles obtained from raster maps of actual landscapes. Methods of the paper are applied to several watersheds of Pennsylvania using landcover maps derived from satellite imagery. These examples indicate that characteristic landscape types induce characteristic features in their fragmentation profiles. 相似文献
64.
Barry P Rochelle Donald L. Stevens M. Robbins. Church 《Journal of the American Water Resources Association》1989,25(3):491-498
ABSTRACT: The U.S. Environmental Protection Agency (EPA) in cooperation with the U.S. Geological Survey (USGS) conducted an analysis to quantify the uncertainty associated with interpolating runoff to specific sites using a runoff contour map. We interpolated runoff to 93 gaged watersheds from a runoff contour map using (1) hand interpolation to the watershed outlet, (2) a computer interpolation to the watershed outlet, and (3) hand interpolation to the watershed centroid. We compared the interpolated values to the actual gaged values and found that there was a bias in the average interpolated value for runoff estimated at basin outlets, with interpolated values being less than the actual. We found no significant difference between the hand interpolation method and the computer interpolation method except that the computer method tended to have higher variability due to factors inherent to the software used. There were no strong spatial correlations or regional patterns in the runoff interpolations, which indicates that there are no regional biases introduced in the development of the contour map. We determined that we could estimate runoff, on the average, within approximately 8.9 cm (3.5 in; 15 percent) of the measured value using the three methods. The results of this work indicate that runoff contour maps can he used in regional studies to estimate runoff to ungaged systems with quantifiable uncertainty. 相似文献