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61.
Analysis of Sediment Retention in Western Riverine Wetlands: The Yampa River Watershed,Colorado, USA
We quantified annual sediment deposition, bank erosion, and sediment budgets in nine riverine wetlands that represented a watershed continuum for 1 year in the unregulated Yampa River drainage basin in Colorado. One site was studied for 2 years to compare responses to peak flow variability. Annual mean sediment deposition ranged from 0.01 kg/m2 along a first-order subalpine stream to 21.8 kg/m2 at a sixth-order alluvial forest. Annual mean riverbank erosion ranged from 3 kg/m-of-bank at the first-order site to 1000 kg/m at the 6th-order site. Total sediment budgets were nearly balanced at six sites, while net export from bank erosion occurred at three sites. Both total sediment deposition (R2 = 0.86, p < 0.01) and bank erosion (R2 = 0.77, p < 0.01) were strongly related to bankfull height, and channel sinuosity and valley confinement helped to explain additional variability among sites. The texture and organic fraction of eroded and deposited sediment were relatively similar in most sites and varied among sites by watershed position. Our results indicate that bank erosion generally balances sediment deposition in riverine wetlands, and we found no distinct zones of sediment retention versus export on a watershed continuum. Zones of apparent disequilibrium can occur in unregulated rivers due to factors such as incised channels, beaver activity, and cattle grazing. A primary function of many western riverine wetlands is sediment exchange, not retention, which may operate by transforming materials and compounds in temporary sediment pools on floodplains. These results are considered in the context of the Hydrogeomorphic approach being implemented by the U.S. government for wetland resource management. 相似文献
62.
Wendy L. Berelson Paul A. Caffrey Jeffrey D. Hamerlinck 《Journal of the American Water Resources Association》2004,40(5):1231-1246
ABSTRACT: In 2002, Wyoming became the first state to complete development of a statewide 1:24,000‐scale Watershed Boundary Dataset (WBD) under the new Federal Standards for Delineation of Hydrologic Unit Boundaries. The product was developed through the coordinated efforts of numerous state, federal, and local entities both within Wyoming and in neighboring states. Development of a comprehensive, standardized hydrologic unit boundary dataset in a “headwaters” state such as Wyoming poses a number of unique challenges. This paper details the WBD's development in Wyoming, highlighting technical methodology development and interagency coordination strategies. Evolution of the WBD standard is reviewed, addressing inconsistencies between definitions for hydro‐logic units and “true” watershed delineations. While automated methods are improving, manual and semi‐automated techniques continue to serve as valuable approaches to hydrologic unit boundary delineation given the quality of digital terrain models and the multijurisdictional nature of watershed based management. This case study provides insight on future development and maintenance of the WBD within and across other states and regions of the country and on opportunities for linking the WBD to related water resource geospatial data products like the National Hydrography Dataset. 相似文献
63.
Role of Adaptive Management for Watershed Councils 总被引:1,自引:0,他引:1
Habron G 《Environmental management》2003,31(1):0029-0041
Recent findings in the Umpqua River Basin in southwestern Oregon illustrate a tension in the rise of both community-based
and watershed-based approaches to aquatic resource management. While community-based institutions such as watershed councils
offer relief from the government control landowners dislike, community-based approaches impinge on landowners' strong belief
in independence and private property rights. Watershed councils do offer the local control landowners advocate; however, institutional
success hinges on watershed councils' ability to reduce bureaucracy, foster productive discussion and understanding among
stakeholders, and provide financial, technical, and coordination support. Yet, to accomplish these tasks current watershed
councils rely on the fiscal and technical capital of the very governmental entities that landowners distrust. Adaptive management
provides a basis for addressing the apparent tension by incorporating landowners' belief in environmental resilience and acceptance
of experimentation that rejects “one size fits all solutions.” Therefore community-based adaptive watershed management provides
watershed councils a framework that balances landowners' independence and fear of government intrusion, acknowledges the benefits
of community cooperation through watershed councils, and enables ecological assessment of landowner-preferred practices. Community-based
adaptive management integrates social and ecological suitability to achieve conservation outcomes by providing landowners
the flexibility to use a diverse set of conservation practices to achieve desired ecological outcomes, instead of imposing
regulations or specific practices. 相似文献
64.
Serveiss VB 《Environmental management》2002,29(2):145-154
Considerable progress in addressing point source (end of pipe) pollution problems has been made, but it is now recognized
that further substantial environmental improvements depend on controlling nonpoint source pollution. A watershed approach
is being used more frequently to address these problems because traditional regulatory approaches do not focus on nonpoint
sources. The watershed approach is organized around the guiding principles of partnerships, geographic focus, and management
based on sound science and data. This helps to focus efforts on the highest priority problems within hydrologically-defined
geographic areas. Ecological risk assessment is a process to collect, organize, analyze, and present scientific information
to improve decision making. The U.S. Environmental Protection Agency (EPA) sponsored three watershed assessments and found
that integrating the watershed approach with ecological risk assessment increases the use of environmental monitoring and
assessment data in decision making. This paper describes the basics of the watershed approach, the ecological risk assessment
process, and how these two frameworks can be integrated. The three major principles of watershed ecological risk assessment
found to be most useful for increasing the use of science in decision making are (1) using assessment endpoints and conceptual
models, (2) holding regular interactions between scientists and managers, and (3) developing a focus for multiple stressor
analysis. Examples are provided illustrating how these principles were implemented in these assessments. 相似文献
65.
/ A watershed-based approach for screening-level assessment of nonpoint source pollution from inactive and abandoned metal mines was developed and illustrated. The methodology was designed to use limited stream discharge and chemical data from synoptic surveys to derive key information required for targeting impaired waterbodies and critical source areas for detailed investigation and remediation. The approach was formulated based on the required attributes of an assessment methodology, information goals for targeting, attributes of data that are typical of basins with inactive mines, and data analysis methods that were useful for the case study. The methodology is presented as steps in a framework including evaluation of existing data/information and identification of data gaps; definition of assessment information goals for targeting and monitoring design; data collection, management, and analysis; and information reporting and use for targeting. Information generated includes the type and extent of and critical conditions for water-quality impairment, concentrations in and loadings to streams, differences between concentrations in and loadings to streams, and risks of exceeding target concentrations and loadings. Data from the Cement Creek Basin, located in the San Juan Mountains of southwestern Colorado, USA, were used to help develop and illustrate application of the methodology. The required information was derived for Cement Creek and used for preliminary targeting of locations for detailed investigation and remediation. Application of the approach to Cement Creek was successful in terms of cost-effective generation of information and use for targeting.KEY WORDS: Water quality assessment; Nonpoint source pollution; Inactive mines; Watershed 相似文献
66.
Derek Armitage 《Environmental management》1995,19(4):469-479
Sustainable environmental planning and management require effective integration of ecological, socioeconomic, and institutional
elements. This paper presents an integrative methodological framework for sustainable environmental planning and management.
The development of this integrative framework is accomplished by combining two complementary analytical approaches—Hufschmidt's
conceptual framework for watershed planning and management and the ABC resource survey method. The combined methodological
framework seeks to delineate and synthesize essential ecological information utilizing an integrative resource survey method.
This method generates classifications of environmental significance and constraint. Areas of environmental significance and
constraint are then linked to appropriate and acceptable resource management actions, implementation tools (e.g., education,
technical assistance), and institutional and organizational arrangements. The integrative methodological framework was developed
for application in the Rio Fortuna watershed in Costa Rica's Arenal Conservation Area. The watershed is characterized by a
variety of land and resource uses, including biologically diverse and ecologically fragile protected areas, small-parcel agriculture,
cattle ranching, and tourism. 相似文献
67.
The Ala Wai Canal Watershed Model (ALAWAT) is a planning-level watershed model for approximating direct runoff, streamflow,
sediment loads, and loads for up to five pollutants. ALAWAT uses raster GIS data layers including land use, SCS soil hydrologic
groups, annual rainfall, and subwatershed delineations as direct model parameter inputs and can use daily total rainfall from
up to ten rain gauges and streamflow from up to ten stream gauges. ALAWAT uses a daily time step and can simulate flows for
up to ten-year periods and for up to 50 subwatersheds. Pollutant loads are approximated using a user-defined combination of
rating curve relationships, mean event concentrations, and loading/washoff parameters for specific subwatersheds, land uses,
and times of year. Using ALAWAT, annual average streamflow and baseflow relationships and urban suspended sediment loads were
approximated for the Ala Wai Canal watershed (about 10,400 acres) on the island of Oahu, Hawaii. Annual average urban suspended
sediments were approximated using two methods: mean event concentrations and pollutant loading and washoff. Parameters for
the pollutant loading and washoff method were then modified to simulate the effect of various street sweeping intervals on
sediment loads. 相似文献
68.
J. A. Gillies 《Journal of the American Water Resources Association》1989,25(6):1243-1248
ABSTRACT: Since Saskatchewan assumed the responsibility for managing the Province's water resources in 1930, the importance of the Province's water resources has been recognized by assigning the responsibility for managing the resource to higher levels in the government structure. With such recognition, there tended to be an overlapping of responsibilities that resulted in undefined areas of jurisdiction and duplication of services. Also, there was no opportunity for direct public participation in the management structure. These deficiencies were recognized, and following a series of public hearings a “Cabinet Committee on Water Concerns” in 1983 concluded that the most appropriate government structure for managing the water resources of Saskatchewan would be a Crown corporation. As a result, in 1984 the Saskatchewan Water Corporation was formed and given the responsibility to manage, administer, develop, control, and protect the water and related land resources in Saskatchewan. An important aspect of this responsibility was that the corporation should initiate a process of public involvement. Thus, six “Regional Watershed Advisory Boards” were established. The Advisory Boards provide the Corporation with a linkage to the general public by providing advice, participating in policy revision and development, and assisting Corporation staff in other related water management activities. 相似文献
69.
Effects of forest clearcutting in New England on stream macroinvertebrates and periphyton 总被引:3,自引:0,他引:3
Clearcutting may alter stream biota by changing light, temperature, nutrients, sediment particle size, or food in the stream. We sampled macroinvertebrates during late summer of 1979 in first and second order headwater streams draining both two- and three-year-old clearcuts and nearby uncut reference areas in northern New England, USA. Periphyton were sampled throughout the summer by placing microscope slides in these streams for 13–37 days. Periphyton cell densities on these slides following incubation were about six times higher in cutover than in reference streams. Green algae (Chlorophyceae) accounted for a higher proportion of total cell numbers in cutover than in reference streams, whereas diatoms (Bacillariophyceae) dominated the reference streams. The macroinvertebrate density in cutover streams was 2–4 times greater than that in the reference streams, but the number of taxa collected was similar in both cutover and reference streams. Higher numbers of mayflies (Ephemeroptera) and/or true flies (Diptera) in the cutover streams accounted for the differences. Because nutrient concentrations in the cutover streams were nearly the same as those in the reference streams, these differences in macroinvertebrate and periphyton densities were apparently caused by higher light levels and temperature in the streams in the clearcuts. Leaving buffer strips along streams will reduce changes in stream biology associated with clearcutting.Contribution from the Northeastern Forest Experiment Station, USDA Forest Service, Durham, New Hampshire 03824, USA. 相似文献
70.
Most nonpoint source pollution problems on forest lands can be controlled by careful planning and management of specific critical areas. Critical areas include sites with high mass and surface erosion hazards, overland flow areas, and the riparian zone. Some guides for identifying critical areas are presented along with examples of land-use constraints that might be applied. 相似文献