全文获取类型
收费全文 | 2826篇 |
免费 | 209篇 |
国内免费 | 507篇 |
专业分类
安全科学 | 240篇 |
废物处理 | 47篇 |
环保管理 | 667篇 |
综合类 | 1389篇 |
基础理论 | 432篇 |
环境理论 | 3篇 |
污染及防治 | 102篇 |
评价与监测 | 104篇 |
社会与环境 | 412篇 |
灾害及防治 | 146篇 |
出版年
2024年 | 20篇 |
2023年 | 45篇 |
2022年 | 98篇 |
2021年 | 114篇 |
2020年 | 90篇 |
2019年 | 83篇 |
2018年 | 104篇 |
2017年 | 141篇 |
2016年 | 168篇 |
2015年 | 143篇 |
2014年 | 120篇 |
2013年 | 194篇 |
2012年 | 193篇 |
2011年 | 221篇 |
2010年 | 189篇 |
2009年 | 157篇 |
2008年 | 141篇 |
2007年 | 183篇 |
2006年 | 206篇 |
2005年 | 146篇 |
2004年 | 98篇 |
2003年 | 114篇 |
2002年 | 104篇 |
2001年 | 81篇 |
2000年 | 67篇 |
1999年 | 53篇 |
1998年 | 39篇 |
1997年 | 29篇 |
1996年 | 24篇 |
1995年 | 27篇 |
1994年 | 21篇 |
1993年 | 15篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 12篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1975年 | 6篇 |
1973年 | 6篇 |
1972年 | 3篇 |
1971年 | 5篇 |
排序方式: 共有3542条查询结果,搜索用时 218 毫秒
811.
Abstract: Noise may drive changes in the composition and abundance of animals that communicate vocally. Traffic produces low‐frequency noise (<3 kHz) that can mask acoustic signals broadcast within the same frequency range. We evaluated whether birds that sing within the frequency range of traffic noise are affected by acoustic masking (i.e., increased background noise levels at the same frequency of vocalizations reduce detection of vocalization) and are less abundant in areas where traffic noise is loud (44–57 dB). We estimated occupancy, the expected probability that a given site is occupied by a species, and detection probabilities of eight forest‐breeding birds in areas with and without traffic noise as a function of noise and three measures of habitat quality: percent forest cover, distance from plot center to the edge of forest, and the number of standing dead trees or snags. For the two species that vocalize at the lowest peak frequency (the frequency with the most energy) and the lowest overall frequency (Yellow‐billed Cuckoo [Coccyzus americanus] and White‐breasted Nuthatch [Sitta carolinensis]), the presence of traffic noise explained the greatest proportion of variance in occupancy, and these species were 10 times less likely to be found in noisy than in quiet plots. For species that had only portions of their vocalizations overlapped by traffic noise, either forest cover or distance to forest edge explained more variation in occupancy than noise or no single variable explained occupancy. Our results suggest that the effects of traffic noise may be especially pronounced for species that vocalize at low frequencies. 相似文献
812.
Robert Coates 《Disasters》2021,45(1):86-106
Disaster education outcomes are highly dependent on the political context of that education. Based on a rich, in‐depth case study of the creation of community monitors in a landslide and flood‐prone city in southeast Brazil, this paper demonstrates how developmental and political environments add much additional nuance to existing theories of behaviourist and transformative education for disaster preparedness and mitigation. Beyond identifying the benefits of education, it argues that disaster risk reduction outcomes are reliant on governance frameworks that alter over time. The study reveals the political complexity associated with programme implementation and cites the perspectives of a number of participants. Disaster education is shown to be the necessary yet underappreciated twin of the militarised and technical approaches that dominate disaster response in Brazil. Understated, however, is education's situatedness: how it can become an arena of conflict between government and civil actors over matters of state and society in increasingly hazardous urbanisation settings in Latin America. 相似文献
813.
This paper argues that there is much to be gained when we view struggles to cultivate food in the city through the lens of Henri Lefebvre's concept of the right to the city. Lefebvre's idea helps us better perceive the radical political and ecological potential of those struggles. And in the empirical details of the struggles we can see concretely the key action in Lefebvre's concept, an action that is only abstract in his work: urban inhabitants becoming active and producing and managing space for themselves. 相似文献
814.
Evaluating long-term urban resilience through an examination of the history of green spaces in Tokyo
Long-term urban resilience requires urban systems with the capacity to respond to change and disturbance and to enhance the conditions for lasting wellbeing. Over the past century Tokyo has demonstrated impressive resilience, especially a capacity to reorganise and rebuild in response to successive major disturbances. Throughout these recoveries, the city-region maintained a focus on re-establishing, improving and maintaining international competitiveness through industrial development. Green spaces in Tokyo provided a flexible, but gradually disappearing resource. Today, to meet the needs of its ageing and minimally expanding population for enhanced wellbeing, Tokyo requires active transition planning covering many intertwined factors, but the adaptive capacity provided by the green space resource is no longer available. The Tokyo case underscores the risk inherent in the depletion of non-renewable resources (in this instance, green space) to secure immediate recovery and accommodate growth and short-term resilience at the expense of long-term resilience. 相似文献
815.
Gerda R. Wekerle 《Local Environment》2015,20(10):1175-1193
This paper addresses issues of access to land for food production in Toronto by offering fresh perspectives on urban agriculture in the neo-liberal city of the global north. It examines attempts to scale up urban agriculture that emphasise changing the relationships between land access, property and new collaborative relationships among different stakeholders. These initiatives involve renegotiating access to land for growing food between private property owners and landless growers, concomitant shifts in control over valued resources and commercialisation. These shifts are often based on relations of trust within a sharing economy rather than public battles over political decisions to develop urban agriculture lands. Growing food on private lands in the city is political in challenging taken-for-granted ideas and practices of property and urban agriculture. New approaches offer options for training and income, as well as expanding the land base for urban agriculture. Small-scale farming projects are affirmative political manoeuvres. They challenge urban residents to consider land for food production across the categories of public and private property. We document three approaches that challenge current property relations: temporary use of a development site through “soft” squatting; redesignating suburban backyards for farmer training and community-based and private food production; and garden sharing of private home backyards for urban food production and commercial growing. Such initiatives articulate alternative visions of sustainability and food security that rely on principles of collaboration and a sharing economy that challenge prevailing notions of property ownership and food security. 相似文献
816.
Daniela A. Guitart Catherine M. Pickering 《Journal of Environmental Planning and Management》2015,58(2):189-212
While claims about the environmental benefits of community gardens abound, few researchers have systematically assessed the ecological integrity of gardening practices. This study investigated gardening practices in 50 community gardens in Brisbane and Gold Coast cities, Australia. The study aimed to better understand how gardening practices might affect the ecological viability of community gardens. Factors investigated included: garden bio-physical characteristics, operators’ motivations, gardeners’ socio-demographic backgrounds, garden facilities and types of plants grown. Two broad types of gardens were identified: permaculture (21 gardens) and non-permaculture (29 gardens). Permaculture gardens used lower-impact gardening practices. Findings have policy implications for environmental planning and management. 相似文献
817.
针对城市景观水的水质状况加剧恶化,本文对比在不同情况下用氯化铁及聚合氯化铝处理景观水,探讨了投加量、搅拌速度、搅拌时间、静沉时间以及pH对景观水有机物和浊度去除率的影响.结果表明:当水样pH值在6~8之间时,投加4~6mL混凝剂后,当先中速搅拌(120 r/min)2 min,最后慢速搅拌(60 r/min)搅拌10 min.此后静沉35 min,此时CODcr去除率及浊度去除率都可达到最佳情况;其中pH为8时,硫酸铁对CODcr去除率可达82%,浊度去除率率为92%;当PH为7时PAC对城市景观水CODcr的去除可达84%,浊度去除率率为96%.聚合氯化铝的处理效果优于硫酸铁,故而得出处理城市景观水时更适合选用聚合氯化铝. 相似文献
818.
819.
820.
中国城市污水厂污泥处置现状研究 总被引:3,自引:0,他引:3
针对中国城市污水厂污泥处置现状问题,概述了国内外常规污泥处置目标和常规污泥处置方式,主要包括填埋处理的方式、污泥焚烧的方法、污泥土地利用的措施,并对目前在中国的适用情况进行了探讨.目前常用的几种常规污泥处置方法各有利弊,也在不断的发展,对于中国各城市来说不可能仅局限于一种处置方法,应结合每个城市的具体情况且还需与城市整体发展趋势相适应.只有这样才能处理好中国城市污水厂污泥处置.保证人民生活在蓝天碧水的环境之中. 相似文献