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131.
JoAnn M. Hanowski Peter T. Walter Gerald J. Niemi 《Journal of the American Water Resources Association》2002,38(3):633-639
ABSTRACT: Forest buffers adjacent to water bodies are widely prescribed in forest management to protect ecological functions of riparian systems. To date, buffers have been applied on the landscape uniformly without quantifying their effectiveness or the effects they have on landscape characteristics. Our objective was to quantify landscape characteristics (amount of edge and interior forest) when buffers were applied to water bodies in a 100 by 100 km area of northern Minnesota. We used a Landsat classified image in a geographic information system platform to apply two buffer widths ?28.5 m and 57 m — to water bodies, including nonforested wetlands, intermittent or perennial streams, and lakes. A total of 107,141 ha (18.3 percent) of the forest area was adjacent to and within 28.5 m of these water bodies, while 201,457 ha of forest was within 57 m, representing 34.4 percent of the total forest area. Imposing a 28.5 m buffer on water bodies increased the amount of edge and interior forest in the study area. When water bodies were buffered with a 57 m forest strip, we found a slight increase in forest edge from the current condition, and this buffer width resulted in the largest amount of interior forest. Interior forest increased with the 57 m buffer due to the density of water bodies in this region; adjacent water bodies coalesced when buffers were applied and formed isolated forest islands that contained forest interior habitat. Instead of wholesale application of set width riparian buffers, we suggest that ecological conditions of riparian areas be evaluated on a site level and that areas that currently provide important riparian conditions be maintained on the landscape with appropriate management practices. 相似文献
132.
James E. Evans Norman S. Levine Sheila J. Roberts Johan F. Gottgens Diane M. Newman 《Journal of the American Water Resources Association》2002,38(6):1549-1565
ABSTRACT: The proposed removal of Ballville Dam was assessed by (1) using a new Geographic Information Systems (GIS) based method for calculating reservoir sediment storage, (2) evaluating sediment properties and contamination from core data, and (3) assessing downstream impacts from sediment routing calculations. A 1903 (pre‐dam) map was manipulated using GIS to recreate the reservoir bathymetry at time of dam construction and used in combination with a detailed 1993 bathymetric survey to calculate sediment volumes and thickness. Reservoir sediment properties and geochemistry were determined from 14 sediment vibracores. Annual sedimentation rates varied from 1.7 to 4.3 g/cm2/yr based on Cesium‐137 (137Cs) and Lead‐210 (210Pb) geochronology and dated flood layers. The pore fluid geochemistry (Ba, Co, Cu, Mn) of four cores showed surficial enrichments in Cu, while Co and Mn show secondary peaks within the sediments. GIS calculations showed that a designed channel through the former reservoir able to accommodate the 10 percent Probable Maximum Flood (PMF) would require removing approximately 0.35 million m3 of sediment (27 percent of the reservoir fill), either by dredging at a cost of up to $6.3 million or by releasing fine grained sediment downstream. A sediment routing model was applied for the critical 6 km downstream using four cross sections. The sediment routing model predicts that, for flows exceeding minimum Mean Daily Flow (1924 to 1998 data), greater than 90 percent of this sediment would be transported through downstream reaches into Lake Erie (Sandusky Bay). 相似文献
133.
铁路局安全管理信息系统的研究与设计 总被引:4,自引:2,他引:4
铁路局安全管理信息系统是铁路现代化安全管理体系中安全信息综合应用的重要组成部分 ,是安全信息分析、安全决策的关键。通过对铁路局安全监控业务的分析及对铁路现有信息系统资源的利用 ,因地制宜地提出建立以铁路局为安全信息处理、分析的第一级信息中心 ,各个铁路分局为第二级信息中心 ,基层站段为信息输入终端的三级安全管理信息系统。信息系统在分布式数据库的基础上应用了一定的数学模型对保存的各类安全检查信息进行比较分析 ,从而使路局安全监察部门通过对上报的安全信息进行分析和预警 ,实现对安全隐患的监控和整改 ,形成闭环管理 ,力求把安全管理从传统的事后追踪变为事前的预防控制 相似文献
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136.
公众参与是环境影响评价工作中的重要环节,也是以人为本的发展理念在环评领域的落脚点和基石。从环境影响评价公众参与实践出发,梳理了开展公众参与的依据,分析了环境影响评价公众参与实践中存在的问题,探讨了提高环境影响评价公众参与有效性的措施。 相似文献
137.
Quevauviller P 《Environmental science and pollution research international》2007,14(5):297-307
Science-policy integration is one of the many complex challenges that scientific and policy-making communities are facing.
It involves knowledge sharing and exchanges among a wide range of disciplines and actors. In many instances, the lack of proper
communication and of a coordination mechanism leads to research outputs not being used or simply known by policy-makers, and
to policy research needs not being communicated to the scientific communities in a timely fashion. This paper discusses the
integration of scientific and technological progress into the policy-making and implementation process, with emphasis on water
policies. It highlights the need and complexity of developing a knowledge-based approach which would enable to lead to an
operational science-policy interface linked to WISE (Water Information System for Europe), including the newly developed WISERTD
webportal ().
The views expressed in this paper are purely those of the author and do not in any circumstances reflect an official position
of the European Commission. 相似文献
138.
Sharon E. Clarke Kelly M. Burnett Daniel J. Miller 《Journal of the American Water Resources Association》2008,44(2):459-477
Abstract: Managers, regulators, and researchers of aquatic ecosystems are increasingly pressed to consider large areas. However, accurate stream maps with geo‐referenced attributes are uncommon over relevant spatial extents. Field inventories provide high‐quality data, particularly for habitat characteristics at fine spatial resolutions (e.g., large wood), but are costly and so cover relatively small areas. Recent availability of regional digital data and Geographic Information Systems software has advanced capabilities to delineate stream networks and estimate coarse‐resolution hydrogeomorphic attributes (e.g., gradient). A spatially comprehensive coverage results, but types of modeled outputs may be limited and their accuracy is typically unknown. Capitalizing on strengths in both field and regional digital data, we modeled a synthetic stream network and a variety of hydrogeomorphic attributes for the Oregon Coastal Province. The synthetic network, encompassing 96,000 km of stream, was derived from digital elevation data. We used high‐resolution but spatially restricted data from field inventories and streamflow gauges to evaluate, calibrate, and interpret hydrogeomorphic attributes modeled from digital elevation and precipitation data. The attributes we chose to model (drainage area, mean annual precipitation, mean annual flow, probability of perennial flow, channel gradient, active‐channel width and depth, valley‐floor width, valley‐width index, and valley constraint) have demonstrated value for stream research and management. For most of these attributes, field‐measured, and modeled values were highly correlated, yielding confidence in the modeled outputs. The modeled stream network and attributes have been used for a variety of purposes, including mapping riparian areas, identifying headwater streams likely to transport debris flows, and characterizing the potential of streams to provide high‐quality habitat for salmonids. Our framework and models can be adapted and applied to areas where the necessary field and digital data exist or can be obtained. 相似文献
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