全文获取类型
收费全文 | 117篇 |
免费 | 0篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 19篇 |
废物处理 | 8篇 |
环保管理 | 31篇 |
综合类 | 29篇 |
基础理论 | 10篇 |
污染及防治 | 14篇 |
评价与监测 | 5篇 |
社会与环境 | 2篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 2篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2014年 | 5篇 |
2013年 | 6篇 |
2012年 | 4篇 |
2011年 | 10篇 |
2010年 | 1篇 |
2009年 | 11篇 |
2008年 | 16篇 |
2007年 | 4篇 |
2006年 | 2篇 |
2005年 | 5篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 4篇 |
2001年 | 10篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有120条查询结果,搜索用时 78 毫秒
81.
Consistent success in encouraging stair climbing on public access staircases contrasts with equivocal evidence for effectiveness in worksites. This paper tests whether contextual factors may affect stair/elevator choice. The study investigated the impact of elevator availability, pedestrian traffic (number using the elevator and stairs per minute), building occupancy (total individuals in the building) and time of day on stair ascent and descent in a workplace. Stair and elevator choices were monitored by automatic counters every weekday during two phases. In a natural experiment, days with four available elevators were compared with days when three elevators were available. Stair use increased for three elevators compared to four. Increasing building occupancy was associated with increased stair use, whilst increasing pedestrian traffic and time of day was associated with reduced stair use. A follow-up study revealed complimentary effects of building occupancy and time of day on elevator waiting times, indicating that increased stair use by contextual factors reflects increased elevator waiting times. In contrast, shorter waiting times are likely when momentary pedestrian traffic is high and later in the day. Crucially, the magnitude of the effects of these contextual factors was ten times larger than previously reported effects of stair climbing interventions. 相似文献
82.
PROFILE: Risk Assessment as an Environmental Management Tool: Considerations for Freshwater Wetlands
A. Dennis Lemly 《Environmental management》1997,21(3):343-358
/ This paper presents a foundation for improving the risk assessmentprocess for freshwater wetlands. Integrating wetland science, i.e., use of anecosystem-based approach, is the key concept. Each biotic and abiotic wetlandcomponent should be identified and its contribution to ecosystem functionsand societal values determined when deciding whether a stressor poses anunreasonable risk to the sustainability of a particular wetland.Understanding the major external and internal factors that regulate theoperational conditions of wetlands is critical to risk characterization.Determining the linkages between these factors, and how they influence theway stressors affect wetlands, is the basis for an ecosystem approach.Adequate consideration of wetland ecology, hydrology, geomorphology, andsoils can greatly reduce the level of uncertainty associated with riskassessment and lead to more effective risk management. In order to formulateeffective solutions, wetland problems must be considered at watershed,landscape, and ecosystem scales. Application of an ecosystem approach can begreatly facilitated if wetland scientists and risk assessors work together todevelop a common understanding of the principles of both disciplines.KEY WORDS: Ecological risk assessment; Freshwater wetlands;Environmental pollution; Chemical stressors; Physical stressors; Biologicalstressors 相似文献
83.
84.
A hydraulic jump is characterized by strong energy dissipation and mixing, large-scale turbulence, air entrainment, waves,
and spray. Despite recent pertinent studies, the interaction between air bubbles diffusion and momentum transfer is not completely
understood. The objective of this paper is to present experimental results from new measurements performed in a rectangular
horizontal flume with partially developed inflow conditions. The vertical distributions of the void fraction and the air bubbles
count rate were recorded for inflow Froude number Fr
1 in the range from 5.2 to 14.3. Rapid detrainment process was observed near the jump toe, whereas the structure of the air
diffusion layer was clearly observed over longer distances. These new data were compared with previous data generally collected
at lower Froude numbers. The comparison demonstrated that, at a fixed distance from the jump toe, the maximum void fraction
C
max increases with the increasing Fr
1. The vertical locations of the maximum void fraction and bubble count rate were consistent with previous studies. Finally,
an empirical correlation between the upper boundary of the air diffusion layer and the distance from the impingement point
was derived. 相似文献
85.
86.
污泥堆肥对几种花卉的生长响应研究 总被引:24,自引:0,他引:24
施用污泥堆肥后,木槿、月季、美人蕉及旱荷花的开花量增加,花期延长,金枣、龟背竹与五叶地锦的各生长参数也明显增大;土壤理化性质有明显改善;当污泥堆肥施用量小于9kg/m^2时,无因盐分、NO3^--N淋溶及地面径流而造成的环境问题。 相似文献
87.
This study was performed to analyse the technical and economical feasibility of a project concerning the recovery of foundry wastes from a landfill. In such a context, an evaluation of the total amount of residues that could be recovered was performed by using the physical chemical characterization of landfilled wastes: molding and core sands, furnace dusts, finishing dusts, muds, calcium hydroxide and refractory slags. Field tests were realized employing both geophysical methods both the digging of trenches.Two cells of the landfill were investigated by means of geophysical methods using magnetic and electromagnetic techniques. The physical and chemical characterization of wastes was employed in order to determine the best geophysical methods to locate the useful fractions of wastes in landfill and to establish the occurring treatment cycle for the recovery of useful fractions.A cost–benefit analysis was performed to evaluate the feasibility of the proposed landfill mining operation. 相似文献
88.
89.
本文综述污染底泥的修复技术,探讨其发展状况及存在的问题。指出物理修复见效快,但成本高;化学修复成本较低但易造成二次污染;生物修复投入低,处理量大,但处理效率低,。将这三类技术联合使用,取长补短,具有较广阔的发展前景。 相似文献
90.