首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   36篇
  免费   0篇
废物处理   2篇
环保管理   14篇
综合类   3篇
基础理论   2篇
污染及防治   14篇
评价与监测   1篇
  2021年   1篇
  2020年   4篇
  2018年   2篇
  2015年   2篇
  2012年   3篇
  2011年   3篇
  2010年   6篇
  2009年   4篇
  2007年   1篇
  2006年   1篇
  2002年   1篇
  2001年   1篇
  1999年   1篇
  1993年   1篇
  1989年   1篇
  1979年   1篇
  1974年   1篇
  1970年   1篇
  1965年   1篇
排序方式: 共有36条查询结果,搜索用时 15 毫秒
1.
Ambio - Social media images are a novel source of data to assess how people view and value the environment. Access to these images is often free, the volume and spread of images is expanding...  相似文献   
2.
The Australian Alps, which are of high conservation value, are popular summer bushwalking destinations. Experimental trampling trials using a standardized methodology were conducted to determine the resistance and resilience of the two common vegetation types: tall alpine herbfield and subalpine grasslands. Vegetation parameters were measured in lanes subject to control (no trampling), 30, 100, 200, 500 and 700 passes at five sites prior to trampling, immediately post trampling, 2 weeks, 6 weeks and 1 year post trampling. Vegetation height, cover of graminoids and herbs, as well as net species richness all declined with trampling, while litter cover increased. Thresholds for damage varied between the two communities and among the different vegetation parameters. The resistance indices for the two communities (number of passes resulting in 50% reduction in vegetation cover), however, were similar at around 440–450 passes indicating that these two communities are among the most resistant of the 19 alpine–subalpine communities that have been tested around the world, but only of moderate resistance compared to non-alpine communities. The two communities showed limited recovery with damage still evident 1 year post trampling. This indicates that they have only moderate tolerance to damage due to moderate resistance, but low resilience.  相似文献   
3.
Corn gluten meal (CGM) is potentially a cost-effective raw material for producing a bioderivable thermoplastic. However, CGM disintegrates to a powder subsequent to processing with polar plasticisers, such as water. The hypothesis of this study was that aqueous urea could be used to denature protein within CGM and therefore encourage protein?Cprotein interactions leading to consolidated bioplastics when using water as a plasticiser. To assess this, the effects of aqueous urea on structure and properties of CGM with particular focus on storage were assessed. Processing of CGM with aqueous urea produced consolidated materials. FTIR analysis showed secondary structure was modified during processing, leading to increased amounts of ??-helices and random coils and reduction of the amount of intermolecular ??-sheets and turns. Above 6?wt% free water, the plasticising efficiency of water in processed CGM increased as the amount of denatured proteins increased. Below 6?wt% free water, protein secondary structure did not have a significant influence on thermal and flexural properties. It was found that storage environment and urea concentration influenced the rate of drying, however, the final water content was constant relative to CGM, and not urea. The materials were resistant to cracking at urea concentrations above 8?M, provided the mass loss during storage did not exceed 15?wt%.  相似文献   
4.
ABSTRACT: The objective of the study was to evaluate alternative land developments around New Hampshire lakes. Alternative development patterns, evaluated by their impacts on the lake area environment and area economy, included residential patterns, commercial patterns, and combinations of these two types. Phosphorus loading of the lake water was used as a proxy variable for changes in the lake water quality. Commercial developments yielded the highest revenues to the town and the local area. It also attracted the most lake users to the area as well as contributing the largest phosphorus loading in the lake waters. Residential developments, although contributing high revenues to the businessmen in the area, yielded less net income to the town. Phosphorus loading levels from residential developments were much lower than lake phosphorus loading by commercial developments.  相似文献   
5.
Mountain biking is an increasingly popular, but sometimes controversial, activity in protected areas. Limited research on its impacts, including studies comparing biking with hiking, contributes to the challenges for mangers in assessing its appropriateness. The impacts of mountain bike riding off trail were compared to those of hiking on subalpine grassland in Australia using a modification of a common trampling experimental methodology. Vegetation and soil parameters were measured immediately and two weeks after different intensities of mountain biking (none, 25, 75, 200 and 500 passes across slope, 200 pass up and down slope) and hiking (200 and 500 passes across slope). There were reductions in vegetation height, cover and species richness, as well as changes in species composition and increases in litter and soil compaction with riding. Riding up and down a moderate slope had a greater impact than riding across the slope. Hiking also affected vegetation height, cover and composition. Mountain biking caused more damage than hiking but only at high use (500 passes). Further research including other ecosystems, topography, styles of riding, and weather conditions are required, but under the conditions tested here, hiking and mountain biking appear to be similar in their environmental impacts.  相似文献   
6.
Tourism infrastructure such as walking tracks can have negative effects on vegetation including in mountain regions. In the alpine area around continental Australia's highest mountain, Mt Kosciuszko (2228 m), there is a range of walking tracks (paved, gravel and raised steel mesh surfaces) in addition to an extensive network of informal/non-hardened tracks. Vegetation characteristics were compared between track types on/under tracks, on the track verge, and in the adjacent native vegetation. For a raised steel mesh walkway there was no difference in vegetation under the walkway, on the verge, and 3m away. In contrast, for a non-hardened track there was 35% bare ground on the track surface but no other detectable impacts. Gravel and paved tracks had distinct verges largely comprising bare ground and exotic species. For non-hardened tracks there was an estimated 270 m2 of disturbance per km of track. For wide gravel tracks the combined area of bare ground, exotic plants and gravel was estimated as 4290 m2 per km, while for narrow gravel tracks it was estimated as 2940 m2 per km. For paved tracks there was around 2680 m2 per km of damage. In contrast, there was no detectable effect of raised steel mesh walkway on vegetation highlighting some of the benefits of this surface over other track types.  相似文献   
7.
8.
The impact of Hurricanes Katrina and Rita in 2005 on pollution emissions in the Gulf of Mexico region was investigated using tropospheric column amounts of nitrogen dioxide (NO2) from the Ozone Monitoring Instrument (OMI) on the NASA Aura satellite. Around New Orleans and coastal Mississippi, we estimate that Katrina caused a 35% reduction in NOx emissions on average in the three weeks after landfall. Hurricane Rita caused a significant reduction (20%) in NOx emissions associated with power generation and intensive oil refining activities near the Texas/Louisiana border. We also found a 43% decrease by these two storms over the eastern Gulf of Mexico Outer Continental Shelf mainly due to the evacuation of and damage to platforms, rigs, and ports associated with oil and natural gas production.  相似文献   
9.
Pickering CM  Buckley RC 《Ambio》2010,39(5-6):430-438
Skier numbers, and revenues for the multi-billion-dollar ski industry, are highly sensitive to snow cover. Previous research projected that under climate change, natural snow cover will become inadequate at 65% of sites in the Australian ski resorts by 2020. Resorts plan to compensate for reduced snowfall through additional snowmaking. For the six main resorts, however, this would require over 700 additional snow guns by 2020, requiring approximately US $100 million in capital investment, and 2,500-3,300 ML of water per month, as well as increased energy consumption. This is not practically feasible, especially as less water will be available. Therefore, low altitude ski resorts such as these may not be able to rely on snowmaking even for short-term adaptation to climate change. Instead, they are likely to seek conversion to summer activities and increased property development.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号