全文获取类型
收费全文 | 111篇 |
免费 | 10篇 |
专业分类
废物处理 | 7篇 |
环保管理 | 21篇 |
综合类 | 18篇 |
基础理论 | 28篇 |
污染及防治 | 31篇 |
评价与监测 | 9篇 |
社会与环境 | 7篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 9篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 6篇 |
2011年 | 16篇 |
2010年 | 11篇 |
2009年 | 8篇 |
2008年 | 9篇 |
2007年 | 1篇 |
2006年 | 5篇 |
2005年 | 9篇 |
2004年 | 1篇 |
2003年 | 5篇 |
2002年 | 7篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1993年 | 2篇 |
1962年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 31 毫秒
101.
The ecological integrity of a lake as a whole can only beassessed through an adequate sampling strategy. Spatialheterogeneity of phytoplankton as well as vertical andhorizontal variability of physical and chemical variables wereestimated from 57 stations at four seasons differing in theirhydrological regime. Resolution of grid positions, located byGPS, was 250 m near the impact site, 500 m for the southernpart of the lake, and 1000 m in the northern part. Data areanalysed by conventional gridding methods as well as in threedimensions with a novel GIS-technique. Horizontal large scaledifferences in several variables are associated withhydrological situations. Local variability in the southern baywas due to input of industrial tailings at times. Spatialvariation of phytoplankton biomass estimated as chlorophyll-aand relevant associated environmental variables were analysedusing a graphical multimetric approach. With this technique,the directly impacted area can be evaluated relative to theremaining part of the lake. The lake is then compared with tworeference lakes, one within the same catchement, the other ina different water-shed. An index of ecological integrity wasdeveloped describing multimetric intra- and interspecific lakevariability. The final index was used to describe the statusof lake water quality relative to a `undisturbed' referencelake. Results showed that Traunsee is ecologically intactalthough its chemistry differs substantially from an`external' reference. 相似文献
102.
103.
104.
Nicole C. Bouvier-Brown Rupert Holzinger Katrin Palitzsch Allen H. Goldstein 《Atmospheric environment (Oxford, England : 1994)》2009,43(2):389-401
Multiple field studies have suggested chemistry within a forest canopy is poorly understood due to inadequate detection and quantification of reactive biogenic emissions, such as terpenes. To measure emission rates of terpenes at Blodgett Forest, a coniferous forest in the Sierra Nevada mountains of California, we placed enclosures over branches of the dominant species at the site – Ponderosa pine, manzanita, and ceanothus – in the summer of 2005. Zero air, with ambient CO2 concentrations, flowed through the chamber system and volatile organic compound (VOC) emission measurements were made by proton transfer reaction mass spectrometry (PTR-MS), solid phase microextraction (SPME) on fibers followed by direct injection into a gas chromatograph with an ion trap mass spectrometer (GC-ITMS), and by in situ GC with a flame ionization detector (GC-FID). We show that previously undetected sesquiterpenes and methyl chavicol significantly contribute to the total reactive biogenic emission profile from this field site. 相似文献
105.
Ryan Bailey Hendrik Rathjens Katrin Bieger Indrajeet Chaubey Jeffrey Arnold 《Journal of the American Water Resources Association》2017,53(2):400-410
This article presents SWATMOD‐Prep, a graphical user interface that couples a SWAT watershed model with a MODFLOW groundwater flow model. The interface is based on a recently published SWAT‐MODFLOW code that couples the models via mapping schemes. The spatial layout of SWATMOD‐Prep guides the user through the process of importing shape files (sub‐basins, hydrologic response units [HRUs], river network) from an existing SWAT model, creating a grid, performing necessary geo‐processing operations to link the models, writing out SWAT‐MODFLOW files, and running the simulation. The option of creating a new single‐layer MODFLOW model for near‐surface alluvial aquifers is available, with the user prompted to provide groundwater surface elevation (through a digital elevation model), aquifer thickness, and necessary aquifer parameter values. The option of simulating nitrate transport in the aquifer also is available, using the reactive transport model RT3D. The interface is in the public domain. It is programmed in Python, with various software packages used for geo‐processing operations (e.g., selection, intersection of rasters) and inputting/outputting data, and is written for Windows. The use of SWATMOD‐Prep is demonstrated for the Little River Experimental Watershed, Georgia. SWATMOD‐Prep and SWAT‐MODFLOW executables are available with an accompanying user's manual at: http://swat.tamu.edu/software/swat-modflow/ . The user's manual also accompanies this article as Supporting Information. 相似文献
106.
Distribution of Selected Soil and Water Conservation Practices in the U.S. as Identified with Google Earth
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Michael White Leighton Haglund Marcus Gloe Katrin Bieger Brandon Namphong Marilyn Gambone Eric Hardy Jungang Gao Haw Yen Jeff Arnold 《Journal of the American Water Resources Association》2017,53(5):1229-1240
The proper representation of conservation practices on agricultural lands is an important factor in large‐scale assessments of water quality in the United States. Unfortunately, there are few publicly available data sources at the local level and even fewer at the national scale. In this research, randomly selected points within agricultural lands were examined for selected conservation practices using Google Earth aerial imagery by a team of interpreters. In total, 13,530 points had field boundaries digitized, and were subsequently examined and classified. The presence of terraces, grassed waterways, contour farming, center pivot irrigation, strip cropping, ponds, riparian vegetation, filter strips, and land cover were noted. Subjectivity among interpreters was evaluated using duplicate samples and was found to be similar to image misclassification rates in other research. Conservation practice adoption rates for selected major river basins compared favorably with data collected by the Conservation Effects Assessment Project. The frequency of occurrence of each conservation practice was summarized and presented by ecoregion. To facilitate future research, point level data and software source code developed in this research are available via the web at http://nlet.brc.tamus.edu/Conservation . Aerial imagery was found to be a powerful, inexpensive, and easily accessible tool to assess large‐scale conservation practice implementation for certain conservation practices. 相似文献
107.
Introduction to SWAT+, A Completely Restructured Version of the Soil and Water Assessment Tool 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Katrin Bieger Jeffrey G. Arnold Hendrik Rathjens Michael J. White David D. Bosch Peter M. Allen Martin Volk Raghavan Srinivasan 《Journal of the American Water Resources Association》2017,53(1):115-130
SWAT+ is a completely restructured version of the Soil and Water Assessment Tool (SWAT) that was developed to face present and future challenges in water resources modeling and management and to meet the needs of the worldwide user community. It is expected to improve code development and maintenance; support data availability, analysis, and visualization; and enhance the model's capabilities in terms of the spatial representation of elements and processes within watersheds. The most important change is the implementation of landscape units and flow and pollutant routing across the landscape. Also, SWAT+ offers more flexibility than SWAT in defining management schedules, routing constituents, and connecting managed flow systems to the natural stream network. To test the basic hydrologic function of SWAT+, it was applied to the Little River Experimental Watershed (Georgia) without enhanced overland routing and compared with previous models. SWAT+ gave similar results and inaccuracies as these models did for streamflow and water balance. Taking full advantage of the new capabilities of SWAT+ regarding watershed discretization and landscape and river interactions is expected to improve simulations in future studies. While many capabilities of SWAT have already been enhanced in SWAT+ and new capabilities have been added, the model will continue to evolve in response to advancements in scientific knowledge and the demands of the growing worldwide user community. Editor's note: This paper is part of the featured series on SWAT Applications for Emerging Hydrologic and Water Quality Challenges. See the February 2017 issue for the introduction and background to the series. 相似文献
108.
Michael White Marilyn Gambone Haw Yen Prasad Daggupati Katrin Bieger Debjani Deb Jeff Arnold 《Journal of the American Water Resources Association》2016,52(1):269-274
The Soil and Water Assessment Tool (SWAT) is widely used in the United States (U.S.) to simulate hydrology and water quality simulation. Process‐based models like SWAT require a great deal of data to accurately represent the natural world, including topography, land use, soils, weather, and management. With the exception of management, all these data are available nationally from multiple sources. To date, credible SWAT studies in the U.S. have assembled suitable management data (operation scheduling, fertilization application rates, and plant growth parameterization). In this research, we develop a national management database for SWAT using existing U.S. Department of Agriculture data sources. These data are compatible with existing SWAT interfaces and are relatively easy to use. Although management data from local sources is preferred, these data are not always available. This work is intended to fill this void with more reasonable management data than the existing defaults. This national database covers all major cultivated crops and should facilitate improved SWAT applications in the U.S. These data were tested in two case studies and found to produce satisfactory SWAT predictions. The database developed in this research is freely available on the web. 相似文献
109.
110.
Katrin Quiel Annette Becker Volker Kirchesch Andreas Schöl Helmut Fischer 《Regional Environmental Change》2011,11(2):405-421
The effects of changing climatic and socioeconomic conditions on the water quality of the Elbe River were investigated using
the deterministic model QSim. Since the impact of global change on river water quality marks the endpoint of various processes
in the catchment and in the atmosphere, this study was performed within a network of interacting models that determined input
parameters for water quality simulations. The development of phytoplankton and nutrient concentrations under conditions of
global change was modeled along a 700 km stretch of the river. The simulations revealed a strong, scale-dependent effect of
climate change on phytoplankton biomass, leading to a longitudinal shift of the dominating processes (primary productivity
vs. respiration) along the river continuum. Under reduced flow, combined with increasing temperature and global radiation,
phytoplankton biomass increased and phytoplankton maxima shifted in upstream direction, followed by higher system respiration
rates in the adjacent downstream sections. In contrast, higher flow shifted the phytoplankton maximum toward the downstream
sections. Even a drastic reduction of phosphorus inputs from anthropogenic sources had only limited influence on algal biomass,
due to the ability of algal cells to store phosphorus. A strong reduction in P-inputs especially in the headwaters would be
necessary to counterbalance the possible climate-induced effects on algal biomass. 相似文献