全文获取类型
收费全文 | 152篇 |
免费 | 6篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 6篇 |
废物处理 | 6篇 |
环保管理 | 91篇 |
综合类 | 15篇 |
基础理论 | 21篇 |
污染及防治 | 6篇 |
评价与监测 | 1篇 |
社会与环境 | 8篇 |
灾害及防治 | 8篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 6篇 |
2011年 | 11篇 |
2010年 | 4篇 |
2009年 | 11篇 |
2008年 | 4篇 |
2007年 | 13篇 |
2006年 | 2篇 |
2005年 | 7篇 |
2004年 | 5篇 |
2003年 | 1篇 |
2002年 | 9篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有162条查询结果,搜索用时 31 毫秒
11.
12.
13.
14.
ABSTRACT: This study analyzes planning under deterministic and stochastic inflows for the Mayurakshi project in India. Models are developed to indicate the optimal storage of reservoir water, the transfer of water to the producing regions, and the spillage of water from the reservoir, if needed. A deterministic programming model was first formulated to represent the existing situation. A chance-constrained model then was constructed to evaluate potential violations of the deterministic model. Both models were quantified for the command area. Data were collected from surveys of the area and from government agencies. Both the deterministic and change-constrained models suggest a more intensive cropping program in the region. Both emphasize more dependence on rabi and less on kharif crops. The chance-constrained especially suggests use of more water in the rabi season. Important chances in cropping programs and labor use take place under the chance-constrained model. 相似文献
15.
Donald J. Epp C. Edwin Young 《Journal of the American Water Resources Association》1981,17(2):215-224
ABSTRACT: Varying treatment levels to meet seasonal variation in assimilative capacity of streams can reduce total costs of treatment. A mathematical model of a Pennsylvania stream based on a theoretically sound approximation of the physical relationships underlying the distribution of DO in a river system was used to determine discharge constraints for an economic optimization model which produced estimates of sewage treatment cost savings. Increasing the number of flow periods during the year enhances cost reducing opportunities even when land application processes are considered. Also, the least cost treatment process for year around operation may not be the least costly under multiple flow period management. 相似文献
16.
Studies based on information acquired by participative geographic approaches have sought to cope with emergency situations and disasters such as floods. However, the impact of these approaches to flood risk governance systems in order to understand these types of events as a complete risk cycle is still not clear. This paper focuses on analysing the governance possibilities of using participative geographic information like volunteered and public participatory geographic information for flood risk reduction in the case of Santiago de Chile, a city which regularly experiences urban floods during rainy seasons. Based on in-depth interviews and document analysis, our study indicates that a relevant part of the current information used for flood risk reduction efforts is provided to local and regional authorities by the affected population. Though, local actors are not recognized by central agencies as valid agents for the production of official information. Moreover, there are neither instances of communication or deliberation with the community, which reduces the capacity of local actors to discuss possible solutions. Participative geographic instruments are seen as potential mechanisms to strengthen work relations among local actors and authorities, by enhancing new logics for producing and sharing information. The impacts for the current risk governance system though can be diverse depending on the participants' level of commitment of participants and the political relations between actors and agencies. Considered as merely data acquisition and analysis mechanisms, participative instruments reproduce the existing hierarchical top-down structures. Furthermore, local-based approaches can enhance local work, support local diagnostics and increase the decision capacity of citizens. 相似文献
17.
Environmental mitigation plays an important role in the environmentally sustainable development of hydropower resources. However, comprehensive data on mitigation required by the Federal Energy Regulatory Commission (FERC) at United States (US) hydropower projects is lacking. Therefore, our objective was to create a comprehensive database of mitigation required at non-federal hydropower projects and provide a synthesis of available mitigation data. Mitigation data was collated for over 300 plants licensed or relicensed from 1998 through 2013. We observed that the majority of FERC mitigation requirements deal with either hydrologic flows or recreation and that hydropower plants in the Pacific Northwest had the highest number of requirements. Our data indicate opportunities exist to further explore hydropower mitigation in the areas of environmental flows, fish passage, and water quality. Connecting these data with ecological outcomes, actual flow data, and larger landscape level information will be necessary to evaluate the effectiveness of mitigation and ultimately inform regulators, managers, and planners. 相似文献
18.
Water Transactions for Streamflow Restoration,Water Supply Reliability,and Rural Economic Vitality in the Western United States
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)
Eloise Kendy Bruce Aylward Laura S. Ziemer Brian D. Richter Bonnie G. Colby Theodore E. Grantham Leslie Sanchez Will B. Dicharry Emily M. Powell Season Martin Peter W. Culp Leon F. Szeptycki Carrie V. Kappel 《Journal of the American Water Resources Association》2018,54(2):487-504
Across the western United States, environmental water transaction programs (EWTPs) restore environmental flows by acquiring water rights and incentivizing changes in water management. These programs have evolved over several decades, expanding from relatively simple two‐party transactions to multiobjective deals that simultaneously benefit the environment and multiple water‐using sectors. Such programs now represent an important water management tool and provide an impetus for collaboration among stakeholders; yet, most evaluations of their effectiveness focus exclusively on environmental outcomes, without adequate attention to impacts on other water users or local economies. To understand how these programs affect stakeholders, a systematic, multiobjective evaluation framework is needed. To meet this need, we developed a suite of environmental and socioeconomic indicators that can guide the design and track the implementation of water transaction portfolios, and we applied them to existing EWTPs in Oregon and Nevada. Application of the indicators quantifies impacts and helps practitioners design water transaction portfolios that avoid unintended consequences and generate mutually beneficial outcomes among environmental, agricultural, and municipal interests. 相似文献
19.
/ Numerous drainages supporting productive salmon habitat are surrounded by active volcanoes on the west side of Cook Inlet in south-central Alaska. Eruptions have caused massive quantities of flowing water and sediment to enter the river channels emanating from glaciers and snowfields on these volcanoes. Extensive damage to riparian and aquatic habitat has commonly resulted, and benthic macroinvertebrate and salmonid communities can be affected. Because of the economic importance of Alaska's fisheries, detrimental effects on salmonid habitat can have significant economic implications. The Drift River drains glaciers on the northern and eastern flanks of Redoubt Volcano. During and following eruptions in 1989-1990, severe physical disturbances to the habitat features of the river adversely affected the fishery. Frequent eruptions at other Cook Inlet region volcanoes exemplify the potential effects of volcanic activity on Alaska's important commercial, sport, and subsistence fisheries. Few studies have documented the recovery of aquatic habitat following volcanic eruptions. The eruptions of Redoubt Volcano in 1989-1990 offered an opportunity to examine the recovery of the macroinvertebrate community. Macroinvertebrate community composition and structure in the Drift River were similar in both undisturbed and recently disturbed sites. Additionally, macroinvertebrate samples from sites in nearby undisturbed streams were highly similar to those from some Drift River sites. This similarity and the agreement between the Drift River macroinvertebrate community composition and that predicted by a qualitative model of typical macroinvertebrate communities in glacier-fed rivers indicate that the Drift River macroinvertebrate community is recovering five years after the disturbances associated with the most recent eruptions of Redoubt Volcano. KEY WORDS: Aquatic habitat; Volcanoes; Lahars; Lahar-runout flows; Macroinvertebrates; Community structure; Community composition; Taxonomic similarity 相似文献
20.
Although half of the administrative units in China are said to have implemented their local Agenda 21, the promotion of sustainable communities is not pervasive. In this paper, we adopted a relatively untried mode of analysis and a socio-economic context to illustrate the potentials and failures of China's grassroots local government bodies in achieving sustainable waste management. Our study shows that, among the three main functions of sustainable waste management (ensuring environmental hygiene, provision of recycling logistics and changing the consumption pattern of the local community) for local governments, grassroots local government bodies in mainland China are only able to do the minimum, i.e. ensuring environmental hygiene and handling complaints. One of the reasons for the failure is that, despite the emphasis on capacity building in China's Agenda 21, the reality is that no action is taken to empower grassroots local government. Despite the high profile accorded by the Chinese central government to motivating local governments to formulate their own Agenda 21, local sustainability and waste management performance have little relevance to the appraisal systems of these government agents. 相似文献