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21.
Charlie M. Shackleton Fiona Parkin Maphambe I. Chauke Linda Downsborough Ashleigh Olsen Gregg Brill Craig Weideman 《Environment, Development and Sustainability》2009,11(2):229-240
Harvesting of non-timber forest products is an integral component of rural livelihoods throughout the developing world. At
times this is at odds with conservation objectives. Reconciliation of the two requires examination of local level contexts
and needs. This paper reports on the harvesting needs for Ischyrolepis by a rural community in South Africa, against the setting that they had recently been prohibited from harvesting by the local
conservation officials. Interviews were conducted with conservation officials to understand the reasoning for the prohibition.
Local demand for Ischyrolepis was assessed by household surveys, as well as in-depth interviews with traders. The density and size class distribution of
Ischyrolepis was determined using transects. The total annual demand for Ischyrolepis was determined to be approximately only 2.7% of the standing crop. The bulk of the annual demand was for small-scale trade,
the income from which was a primary source of income for the few harvesters. Very little evidence could be found indicating
that harvesting was damaging the resource or its habitat, and local knowledge suggested that the abundance of the species
was stimulated by harvesting. Even if market demand were to increase, the size of the shoots required means that less than
20% of the standing crop could be harvested annually. Current regulations around harvesting are in a state of revision, and
hence confusion prevails regarding if harvesting is permissible, and if so, under what conditions, which is detrimental to
both conservation and livelihoods.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
22.
Three major commodity booms since the second world war are identified and analyzed. In all three, demand shocks predominated as triggers to the commodity price rises. The first boom, in 1950–51, was caused by the massive inventory buildup in response to the Korean war. The second, in 1973–74, was accentuated by widespread harvest failures and by OPEC's market management, which tripled the price of oil. The third boom started in 2004 and has not yet run its course. This time, the explosive growth of China's and India's raw materials demand has played a key role. The first two booms collapsed as the world economy went into recession and excessive inventories were sold out. The third boom may prove more durable since the world economy continues to expand briskly and commodity inventories have remained small. 相似文献
23.
In developing countries, the recycling of municipal solid waste (MSW) as an alternative to the traditional MSW management requires an economic sustainability valuation. From this perspective, the estimation of demand for recycling is crucial. In this paper, we study the case of recycling MSW in Santiago, Chile. We estimate the relation between the monthly amount of MSW separated voluntarily from apartments located in Santiago and the monthly price required to participate in a municipal recycling program. We consider the transference of the municipal cost savings to the owners of the apartments due to the amount of MSW separated for recycling, which is not collected and deposited in the current MSW system. For the estimation, we use concepts from environmental economics and psychology, analyzing the operation and municipal costs incurred by current MSW management and designing and applying a survey based on a contingent valuation method (CVM) approach. The results indicate that the percentage of MSW separated for recycling varies between a 27.98% and 33.18%, that only four MSW types are affected by a variation of the monthly price, and that a reduction of monthly collection trips in the current MSW system from 24 to 18 can be obtained. Additionally, we discuss a number of methodological aspects to be considered in a similar study of valuation of recycling in developing countries. Our conclusion is that Santiago has favorable conditions for the implementation of a recycling program as an alternative to the current MSW system. 相似文献
24.
牛云景 《中国环境管理干部学院学报》2011,21(4):66-69
以汾河运城段几个县界断面底泥和水质为实验目标,采用实验室测定方法,分别对在平水期、枯水期的底泥耗氧(SOD)速率进行测试,并对测试条件进行优化,对结果进行分析。研究表明,无论枯水期还是平水期,SOD总体变化趋势与河流水质污染(化学需氧量、氨氮)趋势基本一致。 相似文献
25.
Emergency resources demand prediction using case-based reasoning 总被引:1,自引:0,他引:1
The demand prediction on emergency resources is the premise and basis of optimal allocation of emergency resources. Nowadays, there are only few researches on this aspect in China and abroad. For this reason, the paper aims at the characteristics of emergency resource demand prediction and presents a method for emergency resource demand prediction using case-based reasoning (CBR), which is also a method based on risk analysis. This prediction method cannot only provide a basis for emergency resource reserve and allocation in future, but also provide a method and model support for the emergency resources allocation decision-making system to be constructed in future. 相似文献
26.
作为科研成果的信息载体,科技期刊有着重要的作用。而处于整个出版工作的中心环节的编辑更应在求新、求快的基础上,坚持求准的原则,不断学习,才能将科技期刊越办越好。 相似文献
27.
Roger H. von Haefen Daniel J. Phaneuf 《Journal of Environmental Economics and Management》2003,45(3):612-630
Continuous and count data demand system models have emerged as attractive alternatives to the discrete choice random utility maximization models (RUMs) that currently dominate the seasonal, multi-site recreation demand literature. This paper compares the frameworks conceptually and investigates their empirical performance with a common data set. Although the two modeling approaches employ substantially different behavioral and econometric assumptions, results from a recreation application based on the 1997 Iowa Wetlands Survey suggest that qualitatively similar policy inferences arise from the competing structures. 相似文献
28.
根据测定BOD5所须具备条件,经过理论推导,得出水样稀释倍数的大致范围,对多种工业废水测试证,表明方法简便易行。 相似文献
29.
Economists advocate for using the price mechanism to manage water scarcity, but complex nonlinear rate structures prevalent in markets for municipal water obscure price signals. We conduct a randomized field experiment that jointly elicits knowledge about the cost of water and examines the impact of improved information on demand by linking a survey to water billing records. Half of our sample of 30,000 single family homeowners are randomly sent an invitation to a survey that asks questions about the water bill and the costs of water-use activities (e.g. the cost of taking a shower), and subsequently provides personalized accurate information. Results show that consumers have poor information about the marginal price of water and overestimate the costs of using water. Respondents are relatively better informed about their total bill and water consumption. In aggregate, respondents increase water use in response to the survey, potentially due to learning that water is cheaper than they previously thought. Increased consumption is concentrated among low users who are more likely to over-estimate the costs of using water. 相似文献
30.
Irrigation pricing policies and its impact on agricultural inputs demand in Tunisia: a DEA-based methodology 总被引:1,自引:0,他引:1
Frija A Wossink A Buysse J Speelman S Van Huylenbroeck G 《Journal of environmental management》2011,92(9):2109-2118
This paper estimates farmers' individual irrigation water demand functions employing the information hidden in individual farmers' technical efficiency. This information is extracted through the development of a new deductive methodology based on inverse Data Envelopment Analysis (DEA) models. The empirical results for Tunisia show that farmers who are more technically efficient have less elastic irrigation water demand functions; these farmers would adjust demand only to a limited extent and they can afford the water price. In contrast, water pricing significantly affects those that are less efficient. These farmers shift towards a different cropping pattern using significantly less water and more land when the price of water increases. Thus, higher water prices would threaten this category's livelihood if their efficiency is not improved. However, if the technical efficiency of these farmers were to improve, then it would be more difficult to reach water saving objectives since their demand will also become highly inelastic. The findings have important implications in view of the objectives of Tunisia water policy which include:full cost recovery, continuity of the irrigation activity, and water saving at the national level. 相似文献