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111.
太湖流域西部圩区陆地生态系统维持和调节功能量化评估 总被引:1,自引:0,他引:1
圩区是南方平原水网地区一种重要的地理单元,圩区陆地生态系统维持和调节功能的研究对于圩区内的土地利用优化、生态环境保护与恢复等都有重要的意义。研究选取太湖流域西部地区的圩区,采用物质量评估的方法,对陆地生态系统的水量调节、净化环境、土壤保持和生境维持等4 种类型的生态服务功能进行了量化评估,研究结果表明:①圩区陆地生态系统年可调节水量43.71×108 m3,削减总氮6 079.72 t,削减总磷734.99 t,保持土壤150.76×104 t,景观综合指数介于0.96~1.11 之间,体现出较大的服务价值;②圩区陆地生态系统维持和调节功能的总量和单位面积量在空间上都存在差异性。从总量来看,宜兴、溧阳和金坛各市区较高,武进、丹徒和丹阳的服务功能总量较低,地形及水系分布是造成这一差异的主要原因;从单位面积的服务功能量来看,丹徒和丹阳较高,金坛、溧阳和宜兴处于一般水平,武进最低,圩区内土地利用方式的不同是造成这一差异的主要原因;③圩内生态系统服务功能的管理和恢复应参考服务能力大小,因地制宜区别对待。生态服务功能较强的市区,应发挥其生态功能的优势;生态服务功能较弱的地区,应采取一定的措施对其生态服务功能进行恢复;④研究成果对于圩内生态环境保护与恢复、土地利用结构优化等也具有参考价值。 相似文献
112.
贝叶斯(Bayes)判别分析理论在安全评价中的应用 总被引:6,自引:1,他引:5
论述了多元统计分析方法中的贝叶斯判别分析方法在安全评价中的应用。通过对原始数据的分析建立起反映被评价对象安全状况的综合指标函数模型,从而简化后续同类评价目标工作量。 相似文献
113.
Herbert D. Drechsler Peter N. Nemetz 《Journal of the American Water Resources Association》1978,14(5):1094-1104
ABSTRACT: The hypothesis of this paper is that the frequently used regulatory practice which employs point estimates in water pollution control objectives, in combination with monitoring at infrequent intervals, is an inadequate scientific procedure for the measurement and control of pollution. The first part of this paper outlines the relevant sampling theory which applies to the measurement of effluent from industrial plants and describes the possible errors in sampling practice which currently affect the interpretation and enforcement of environmental standards. In the second part of the paper, the authors describe briefly the environmental significance of biological damage functions. In the final part of the paper, the authors recommend that existing pollution control regulations be restructured to be more efficient and effective in the protection of both corporate and social interests. By adopting two different approaches to regulation depending upon the nature of the appropriate damage functions and critical fish species, it is possible to reduce significantly the waste of resources. 相似文献
114.
David Karmeli 《Journal of the American Water Resources Association》1978,14(6):1374-1386
ABSTRACT: Land, water, labor, and capital are optimally allocated to crops on a farm, using a procedure that also relates to irrigation frequency and level of improvement in the irrigation system. The procedure is based on formulating outputs and expenditures as well as the functions of irrigation frequency-water and yield. The Generalized Geometric Programming is used to solve the objective function as nonlinear equations are involved. 相似文献
115.
James S. DeBettencourt George L. Peterson 《Journal of the American Water Resources Association》1981,17(6):1050-1055
ABSTRACT: Managers of water related outdoor recreation resources want to provide facilities and recreational opportunities of high quality that are attractive to recreationists. The reported research develops a relevant site quality assessment and measurement procedure called environmental threshold modeling. This modeling procedure is based upon the idea that individuals (i.e., recreationists) have specific, identifiable evaluative criteria which can be expressed as a mathematical function of various site characteristics. The function of interest is called a threshold function because it separates acceptable recreational settings from unacceptable settings. Individual specific threshold functions can be easily aggregated to form a population specific threshold function that estimates the proportion of a population that would find the recreational setting acceptable for some specific activity. Presented in this paper are illustrative calibration results based upon survey data collected from recreational canoeists using the Pine River in Michigan's Manistee National Forest. 相似文献
116.
ABSTRACT. Society has long sought to maximize the welfare of its members by allocating its limited resources so as to provide maximum satisfaction. As long as all of the values that society gains or loses are measured in the market place in terms of price, the process of maximizing through economic models is relatively straightforward. In fact, however, the total value that society receives from the use of its resources is not completely measured through the private market transactions. There are some values created which are external to the market system. The resulting underinvestment in natural resources by the private sector necessitates the entry of the public sector. The presence of intangible benefits and intangible costs has long been recognized, but completely satisfactory methods for including these in the quantitative analysis of benefit-cost have not been developed. Some progress has been made in including recreational values in project analysis via the expenditures method, the Gross National Product method, consumer surplus method, cost method, market value method, and monopoly and discriminating monopoly methods, but little has been done in the area of aesthetic values. Techniques for including such values in project evaluation need to be further researched. Tradeoff models developed by market researchers, the advertising industry, social psychologists and sociologists may have some applicability. Methodology for including proposed multiple objective functions in project analysis is also a critical need. 相似文献
117.
Gregory A. Vaut Cleve E. Willis 《Journal of the American Water Resources Association》1973,9(6):1182-1187
ABSTRACT: In spite of the rather large volume of literature suggesting that non-efficiency objectives ought to be incorporated into water resource planning frameworks, little has been done to date. A partial explanation is that when goals are in conflict we have no “objective” criteria upon which to make the trade-offs. Also, there are problems of measuring the degree to which various policy actions lead to achievement of various goals. Nevertheless, this paper argues that given the magnitude of the possible gains from incorporating these considerations, considerable effort to overcome these problems is justified. Accordingly, we outline some procedures for making these trade-offs and suggest an alternative (practical) planning framework. 相似文献
118.
Scott A. Miller Gary S. Johnson Donna M. Cosgrove Roger Larson 《Journal of the American Water Resources Association》2003,39(3):517-528
ABSTRACT: Changes in irrigation and land use may impact discharge of the Snake River Plain aquifer, which is a major contributor to flow of the Snake River in southern Idaho. The Snake River Basin planning and management model (SRBM) has been expanded to include the spatial distribution and temporal attenuation that occurs as aquifer stresses propagate through the aquifer to the river. The SRBM is a network flow model in which aquifer characteristics have been introduced through a matrix of response functions. The response functions were determined by independently simulating the effect of a unit stress in each cell of a finite difference groundwater flow model on six reaches of the Snake River. Cells were aggregated into 20 aquifer zones and average response functions for each river reach were included in the SRBM. This approach links many of the capabilities of surface and ground water flow models. Evaluation of an artificial recharge scenario approximately reproduced estimates made by direct simulation in a ground water flow model. The example demonstrated that the method can produce reasonable results but interpretation of the results can be biased if the simulation period is not of adequate duration. 相似文献
119.
将多元统计方法中的聚类分析和Fisher判别分析综合应用于安全评价中,评价指标的系统效应权数有效避免了安全评价中人为赋予指标权重对评价结果的影响.分析了评价对象聚类的步骤和结果,探讨了评价对象所属安全等级的Fisher判别方法.最后通过对判别函数的分析与比较得出评价判别结果. 相似文献
120.
Vladimir Kucera Johan Tidblad Katerina Kreislova Dagmar Knotkova Markus Faller Daniel Reiss Rolf Snethlage Tim Yates Jan Henriksen Manfred Schreiner Michael Melcher Martin Ferm Roger-Alexandre Lefèvre Joanna Kobus 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):249-258
A “multi-pollutant exposure programme” reflecting the new pollution situation where SO2 is no longer the dominating pollutant has been performed by the International Co-operative Programme on Effects on Materials,
including Historic and Cultural Monuments (ICP Materials) within the activities of the Convention on Long-range Transboundary
Air Pollution. The main results obtained in the period 1997–2003 are summarised. Dose-response functions are presented for
carbon steel, zinc, copper, bronze and limestone. Parameters involved in the functions include besides SO2 and pH, which were included in the previously developed functions from ICP Materials, also the effect of particulate matter
and HNO3. 相似文献