全文获取类型
收费全文 | 395篇 |
免费 | 8篇 |
国内免费 | 8篇 |
专业分类
安全科学 | 40篇 |
废物处理 | 14篇 |
环保管理 | 93篇 |
综合类 | 48篇 |
基础理论 | 78篇 |
环境理论 | 1篇 |
污染及防治 | 95篇 |
评价与监测 | 27篇 |
社会与环境 | 9篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 10篇 |
2018年 | 10篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 15篇 |
2014年 | 10篇 |
2013年 | 34篇 |
2012年 | 12篇 |
2011年 | 34篇 |
2010年 | 22篇 |
2009年 | 21篇 |
2008年 | 24篇 |
2007年 | 17篇 |
2006年 | 29篇 |
2005年 | 20篇 |
2004年 | 11篇 |
2003年 | 12篇 |
2002年 | 11篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 6篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有411条查询结果,搜索用时 456 毫秒
101.
This study utilizes remote sensing derived forest aboveground biomass (AGB) estimates and ownership information obtained from
the Protected Areas Database (PAD), combining landscape analyses and GIS techniques to demonstrate how different ownerships
(public, regulated private, and other private) relate to the spatial distribution of AGB in New England states of the USA.
“Regulated private” lands were dominated by lands in Maine covered by a Land Use Regulatory Commission. The AGB means between
all pairs of the identified ownership categories were significantly different (P < 0.05). Mean AGB observed in public lands (156 Mg/ha) was 43% higher than that in regulated private lands (109 Mg/ha), or
30% higher than that of private lands as a whole. Seventy-seven percent of the regional forests (or about 9,300 km2) with AGB >200 Mg/ha were located outside the area designated in the PAD and concentrated in western MA, southern VT, southwestern
NH, and northwestern CT. While relatively unfragmented and high-AGB forests (>200 Mg/ha) accounted for about 8% of total forested
land, they were unevenly proportioned among the three major ownership groups across the region: 19.6% of the public land,
0.8% of the regulated private land, and 11.0% of the other private land. Mean disturbance rates (in absolute value) between
1992 and 2001 were 16, 66, and 19 percent, respectively, on public, regulated private, and other private land. This indicates
that management practices from different ownerships have a strong impact on dynamic changes of landscape structures and AGB
distributions. Our results may provide insight information for policy makers on issues regarding forest carbon management,
conservation biology, and biodiversity studies at regional level. 相似文献
102.
Supriyo De Somiranjan Ghosh Raghunath Chatterjee Y-Q Chen Linda Moses Akanchha Kesari Eric P. Hoffman Sisir K. Dutta 《Environment international》2010,36(8):907-917
In this study we have examined the effect of exposure to different congeners of PCBs and their role in oxidative stress response. A metabolically competent human liver cell line (HepG2) was exposed with two prototype congeners of PCBs: coplanar PCB-77 and non-coplanar PCB-153. After the predetermined times of exposure (0–24 h) at 70 μM concentration, the HepG2 cells showed significant apoptotic changes by fluorescent microscopy after 12 h of exposure. Gene set enrichment analysis (GSEA) identified oxidative stress as the predominant enrichment. Further, paraquat assay showed that PCB congeners lead to oxidative stress to different extents, PCB-77 being more toxic. This study, with emphasis on all recommended microarray quality control steps, showed that apoptosis was one of the most significant cellular processes as a result of oxidative stress, but each of these congeners had a unique signature gene expression, which was further validated by Taqman real time PCR and immunoblotting. The pathways involved leading to the common apoptotic effect were completely different. Further in-silico analysis showed that PCB-153 most likely acted through the TNF receptor, leading to oxidative stress involving metallothionein gene families, and causing apoptosis mainly by the Fas receptor signaling pathway. In contrast, PCB-77 acted through the aryl hydrocarbon receptor. It induced oxidative stress through the involvement of cytochrome P450 (CYP1A1) leading to apoptosis through AHR/ARNT pathway. 相似文献
103.
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
104.
Linda S. Gaulke Xiao Weiyang Andrew Scanlon Amanda Henck Tom Hinckley 《Environmental management》2010,45(1):93-104
The administration of Jiuzhaigou National Park in Sichuan Province, China, is in the process of considering a range of upgrades
to their sanitation and wastewater treatment systems. Their case history involves an ongoing series of engineering design
flaws and management failures. The administration of the Park identified sustainability, environmental protection, and education
goals for their sanitation and wastewater treatment system. To meet the goal of sustainability, environmental and economic
concerns of the Park’s administration had to be balanced with socio-cultural needs. An advanced reconnaissance method was
developed that identified reasons for previous failures, conducted stakeholder analysis and interviews, determined evaluation
criteria, and introduced innovative alternatives with records of successful global implementations. This evaluation also helped
the Park to better define their goals. To prevent future failures, the administration of the Park must commit to a balanced and thorough evaluation process for
selection of a final alternative and institute effective long-term management and monitoring of systems. In addition, to meet
goals and achieve energy efficient, cost-effective use of resources, the Park must shift their thinking from one of waste
disposal to resource recovery. The method and criteria developed for this case study provides a framework to aid in the successful
implementation of sanitation projects in both underdeveloped and developed areas of the world, incorporating socio-cultural
values and resource recovery for a complex group of stakeholders. 相似文献
105.
Linking Theory and Practice for Restoration of Step-Pool Streams 总被引:1,自引:0,他引:1
Chin A Anderson S Collison A Ellis-Sugai BJ Haltiner JP Hogervorst JB Kondolf GM O'Hirok LS Purcell AH Riley AL Wohl E 《Environmental management》2009,43(4):645-661
Step-pools sequences are increasingly used to restore stream channels. This increase corresponds to significant advances in
theory for step-pools in recent years. The need for step-pools in stream restoration arises as urban development encroaches
into steep terrain in response to population pressures, as stream channels in lower-gradient areas require stabilization due
to hydrological alterations associated with land-use changes, and as step-pools are recognized for their potential to enhance
stream habitats. Despite an increasingly voluminous literature and great demand for restoration using step-pool sequences,
however, the link between theory and practice is limited. In this article, we present four unique cases of stream restoration
using step-pools, including the evolution of the approaches, the project designs, and adjustments in the system following
restoration. Baxter Creek in El Cerrito, California demonstrates an early application of artificial step-pools in which natural
adjustments occurred toward geomorphic stability and ecological improvement. Restoration of East Alamo Creek in a large residential
development near San Ramon, California illustrates an example of step-pools increasingly used in locations where such a channel
form would not naturally occur. Construction of a step-pool channel in Karnowsky Creek within the Siuslaw National Forest,
Oregon overcame constraints posed by access and the type and availability of materials; the placement of logs allowed natural
scouring below steps. Dry Canyon Creek on the property of the Mountains Restoration Trust in Calabasas, California afforded
a somewhat experimental approach to designing step-pools, allowing observation and learning in the future. These cases demonstrate
how theories and relationships developed for step-pool sequences over the past two decades have been applied in real-world
settings. The lessons from these examples enable us to develop considerations useful for deriving an appropriate course of
design, approval, and construction of artificial step-pool systems. They also raise additional fundamental questions concerning
appropriate strategies for restoration of step-pool streams. Outstanding challenges are highlighted as opportunities for continuing
theoretical work. 相似文献
106.
Educators recognize the ecological, economic, and social components of environmental sustainability. For community-based programs, there is another sustainability trio that, if neglected, will lead to a decline in program quality and function. To be sustainable over the long term, community-based programs must have superior educational quality, clear organizational structure, and continued financial stability. Many educational outreach programs that have neglected this sustainability trio have been weakened or eliminated as they are not seen as priority items during budget reductions. The Master Gardener Program exemplifies this premise, representing a cadre of tens of thousands of university-trained volunteer educators who deliver environmental education to their communities. Over the years, the vision for educational quality, use of clear organizational structures fitting an increased reliance on volunteers, and securing of outside funding for sustainability education have waned in many states, resulting in a lack of university leadership and programmatic devolution. We propose revising outreach education to align with the best practices in adult pedagogy and science by developing a centralized organizational structure and by looking outside traditional university resources for funding opportunities. These strategies can easily be adapted for other community-based outreach programs. 相似文献
107.
Emily A. Botts Genevieve Pence Stephen Holness Kerry Sink Andrew Skowno Amanda Driver Linda R. Harris Philip Desmet Boyd Escott Mervyn Lötter Jeanne Nel Tammy Smith Fahiema Daniels Samuel Sinclair Warrick Stewart Jeffrey Manuel 《Conservation biology》2019,33(6):1235-1246
Systematic conservation planning is intended to inform spatially explicit decision making. Doing so requires that it be integrated into complex regulatory and governance processes, and there are limited instances where this has been achieved effectively. South Africa is a global leader in the application of conservation plans, the outputs of which are widely used for spatial planning and decision making in many spheres of government. We aimed to determine how conservation planning in the country progressed from theory to implementation, and to identify practical actions that enabled this transition, by assessing temporal trends in the characteristics of conservation plans (1990–2017, n = 94). Since 2010 conservation planning has entered an operational period characterized by government leadership of plans, administrative rather than ecological planning domains, decreasing size of planning units, increasing emphasis on end-user products, and scheduled revision of plans. Key actions that enabled this progression include transitioning leadership of plans from scientists to practitioners, building capacity within implementing agencies, creating opportunities to integrate plans in legislative processes, establishing a strong community of practice, adopting implementation-focused methods, and balancing standardization with innovation. Learning from this model will allow other countries, particularly those with a similar megadiverse, developing context, to operationalize conservation planning into spatial planning and decision making. 相似文献
108.
Anne W. Rea Maria J. Zufall Ron W. Williams Linda Sheldon Cynthia Howard-Reed 《Journal of the Air & Waste Management Association (1995)》2013,63(9):1271-1279
ABSTRACT Particulate matter (PM) exposure data from the U.S. Environmental Protection Agency (EPA)-sponsored 1998 Baltimore and 1999 Fresno PM exposure studies were analyzed to identify important microenvironments and activities that may lead to increased particle exposure for select elderly (>65 years old) subjects. Integrated 24-hr filter-based PM2.5 or PM10 mass measurements [using Personal Environmental Monitors(PEMs)] included personal measurements, indoor and outdoor residential measurements, and measurements at a central indoor site and a community monitoring site. A subset of the participants in each study wore passive nephelometers that continuously measured (1-min averaging time) particles ranging in size from 0.1 to ~10 um. Significant activities and locations were identified by a statistical mixed model (p < 0.01) for each study population based on the measured PM2.5 or PM10 mass and time activity data. Elevated PM concentrations were associated with traveling (car or bus), commercial locations (store, office, mall, etc.), restaurants, and working. The modeled results were compared to continuous PM concentrations determined by the nephelometers while participants were in these locations. Overall, the nephelometer data agreed within 6% of the modeled PM2.5 results for the Baltimore participants and within ~20% for the Fresno participants (variability was due to zero drift associated with the nephelometer). The nephelom-eter did not agree as well with the PM10 mass measurements, most likely because the nephelometer optimally responds to fine particles (0.3–2 um). Approximately one-half (54 ± 31%; mean ± standard deviation from both studies) of the average daily PM2.5 exposure occurred inside residences, where the participants spent an average of 83 ± 10% of their time. These data also showed that a significant portion of PM2.5 exposure occurred in locations where participants spent only 4–13% of their time. 相似文献
109.
110.
Magalie Bassan Doulaye Koné Mbaye Mbéguéré Christof Holliger Linda Strande 《Journal of Environmental Planning and Management》2015,58(10):1690-1710
Many factors influence success and failure of large-scale faecal sludge and wastewater treatment projects in low-income countries. Benchmarking indicators and multicriteria analysis were adapted to define key institutional, technical and financial factors, to analyse their interrelations, and understand priorities to consider when planning and managing treatment plants. For the first time, these methods have been combined in a quantitative manner to assess planned and on-going treatment plant projects. This new methodology will aid sanitation utilities, private consultants, and funding institutions to prioritise activities and organise the operation of treatment plants. 相似文献