全文获取类型
收费全文 | 557篇 |
免费 | 11篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 400篇 |
废物处理 | 1篇 |
环保管理 | 56篇 |
综合类 | 25篇 |
基础理论 | 37篇 |
污染及防治 | 12篇 |
评价与监测 | 5篇 |
社会与环境 | 3篇 |
灾害及防治 | 31篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 8篇 |
2021年 | 30篇 |
2020年 | 31篇 |
2019年 | 16篇 |
2018年 | 9篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 18篇 |
2014年 | 21篇 |
2013年 | 15篇 |
2012年 | 13篇 |
2011年 | 30篇 |
2010年 | 29篇 |
2009年 | 32篇 |
2008年 | 17篇 |
2007年 | 23篇 |
2006年 | 14篇 |
2005年 | 19篇 |
2004年 | 22篇 |
2003年 | 16篇 |
2002年 | 14篇 |
2001年 | 14篇 |
2000年 | 13篇 |
1999年 | 26篇 |
1998年 | 19篇 |
1997年 | 10篇 |
1996年 | 17篇 |
1995年 | 14篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有570条查询结果,搜索用时 593 毫秒
321.
Garten CT 《Journal of environmental management》2006,81(4):323-332
A model-based analysis of the effect of prescribed burning and forest thinning or clear-cutting on stand recovery and sustainability was conducted at Fort Benning, GA, in the southeastern USA. Two experiments were performed with the model. In the first experiment, forest recovery from degraded soils was predicted for 100 years with or without prescribed burning. In the second experiment simulations began with 100 years of predicted stand growth, then forest sustainability was predicted for an additional 100 years under different combinations of prescribed burning and forest harvesting. Three levels of fire intensity (low, medium, and high), that corresponded to 17%, 33%, and 50% consumption of the forest floor C stock by fire, were evaluated at 1-, 2-, and 3-year fire return intervals. Relative to the control (no fire), prescribed burning with a 2- or 3-year return interval caused only a small reduction in predicted steady state soil C stocks (< or =25%) and had no effect on steady state tree wood biomass, regardless of fire intensity. Annual high intensity burns did adversely impact forest recovery and sustainability (after harvesting) on less sandy soils, but not on more sandy soils that had greater N availability. Higher intensity and frequency of ground fires increased the chance that tree biomass would not return to pre-harvest levels. Soil N limitation was indicated as the cause of unsustainable forests when prescribed burns were too frequent or too intense to permit stand recovery. 相似文献
322.
Hill MJ Lesslie R Donohue R Houlder P Holloway J Smith J Ritman K 《Environmental management》2006,37(5):712-731
The purpose of this study was to help to inform policy development for the Australian rangelands, and provide a proof of concept
for application of a multi-criteria analysis approach to assessment of competing resource use at continental scale. The study
aimed to identify and locate key natural resource and agricultural production assets in the rangelands, define a number of
measures of potentially threatening processes, and use a multi-criteria approach to identify areas where threatening processes,
agricultural production problems, or valuable natural resources coincided. The analysis used 35 readily available, continental
spatial data layers at 5-km pixel resolution ranked from 1 (low) to 5 (high) under three themed groupings: natural resource
base, production base, and threatening processes. These measures were aggregated into composite indicators to define attributes
such as environmental sensitivity and total grazing pressure. The composites were then compared in a two-way analysis to explore
particular interactions between threatening processes such as pastoralism and mining, and the condition of production and
natural resource assets. These interactions were defined as “tensions” for purposes of this analysis. Example “tensions” included
the association of high grazing intensity with areas of high environmental sensitivity, indicating a risk of land degradation
under adverse climatic conditions. A summary of patterns of tension was obtained by extracting area proportions of high-tension
classes for selected Natural Heritage Trust Regions, which are a basis for Australian Government funding of improved environmental
management. The study provides a basis for further examination of trade-offs in the use of natural assets, opportunities for
improved productivity and sustainability, and social and economic implications. 相似文献
323.
水成膜泡沫在油类表面的窒息作用是扑灭油类火灾的重要机理之一,针对自行开发的快速型泡沫灭火剂开展了其对油池火的窒息灭火特性研究。首先通过老化试验测试了泡沫液的热稳定性,然后对比了不同成分泡沫液在25#变压器油表面的铺展特性,之后研究了不同发泡倍率和成分的泡沫液对油池火的窒息灭火效果及影响规律。研究发现,铺展性能不佳的泡沫液会逐渐丧失窒息能力,而铺展性能优异的泡沫液能持续发挥窒息作用。提升泡沫液热稳定性有利于在油面形成稳定的液膜,隔绝氧气并降低可燃分子挥发速率。此外,发泡倍率较低的泡沫液的流动性更强,在相同液体流量条件下低倍数泡沫的窒息灭火效果更优。自研的快速型泡沫灭火剂在热稳定性和铺展性能两方面均具备优良的性能,因此其窒息灭火效率和抗复燃能力优于现有的大部分同类泡沫灭火剂。 相似文献
324.
城市火灾风险评价的数学模型 总被引:14,自引:5,他引:9
运用专家调查法和层次分析法 ,引入城市火灾危险指数、城市火灾风险指数、城市火灾载荷指数和城市消防抗灾指数的概念 ,建立了城市火灾风险评价的指标体系 ;并以单元系统模糊优选理论为基础 ,构造出城市火灾风险评价的数学模型。 相似文献
325.
中国消防工程及其21世纪的前景 总被引:13,自引:5,他引:8
肖学锋 《中国安全科学学报》2000,10(1):17-21
简要介绍了国内外消防工程学科的发展现状 ,回顾了我国消防工程技术的发展历程 ,对消防工程领域的发展趋势和前景进行了展望和预测。 相似文献
326.
Vadrevu KP Ellicott E Badarinath KV Vermote E 《Environmental pollution (Barking, Essex : 1987)》2011,159(6):1560-1569
Agricultural residue burning is one of the major causes of greenhouse gas emissions and aerosols in the Indo-Ganges region. In this study, we characterize the fire intensity, seasonality, variability, fire radiative energy (FRE) and aerosol optical depth (AOD) variations during the agricultural residue burning season using MODIS data. Fire counts exhibited significant bi-modal activity, with peak occurrences during April-May and October-November corresponding to wheat and rice residue burning episodes. The FRE variations coincided with the amount of residues burnt. The mean AOD (2003-2008) was 0.60 with 0.87 (+1σ) and 0.32 (−1σ). The increased AOD during the winter coincided well with the fire counts during rice residue burning season. In contrast, the AOD-fire signal was weak during the summer wheat residue burning and attributed to dust and fossil fuel combustion. Our results highlight the need for ‘full accounting of GHG’s and aerosols’, for addressing the air quality in the study area. 相似文献
327.
328.
329.
特长公路隧道独立排烟道结构高温安全性研究 总被引:2,自引:0,他引:2
特长公路隧道的火灾安全尤其是火灾通风排烟问题日益受到特别的关注。苍岭隧道是一座长度超过7 km的公路隧道,根据多方咨询意见,其通风排烟系统采用带独立排烟道的纵向通风模式。为了判断排烟道顶隔板结构在火灾高温下的安全性,以火灾动态模拟软件FDS的分析结果为温度边界条件,通过ANSYS对火灾下与常温下顶隔板的内力及变形进行了对比分析,探讨了顶隔板在火灾下的破坏规律,得出了火灾下顶隔板的临界破坏温度及其沿隧道的纵向破坏范围。 相似文献
330.
This paper identifies human factors associated with high forest fire risk in Spain and analyses the spatial distribution of fire occurrence in the country. The spatial units were 6,066 municipalities of the Spanish peninsular territory and Balearic Islands. The study covered a 13-year series of fire occurrence data. One hundred and eight variables were generated and input to a dedicated Geographic Information System (GIS) to model different factors related to fire ignition. After exploratory analysis, 29 were selected to build a predictive model of human fire ignition using logistic regression analysis. The binary model estimated the probability of high or low occurrence of forest fires, as defined by an ignition danger index that is currently used by the Spanish forest service (number of fires divided by forest area in each municipality). Thirteen explanatory variables were identified by the model. They were related to agricultural landscape fragmentation, agricultural abandonment and development processes. The prediction agreement found between the model binary outputs and the historical fire data was 85.3% for the model building dataset (60% of municipalities). A slightly lower predictive power (76.2%) was found for the validation data (the remaining 40%). The probabilistic output of the logistic was significantly related to the raw ignition index (Spearman correlation of 0.710) used by the Spanish Forest Service. Therefore, the model can be considered a good predictor of human-caused fire risk, aiding spatial decisions related to prevention planning in Spanish municipalities. 相似文献