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71.
The cumulative availability curve shows the quantities of a mineral commodity that can be recovered under current conditions from existing resources at various prices. The future availability of a mineral commodity depends on the shape of its cumulative availability curve (determined by geologic considerations, such as the nature and incidence of the available mineral deposits), the speed at which society moves up the curve (determined by future demand and the extent to which this demand is satisfied by recycling), and shifts in the curve (determined by cost-reducing technological change and other factors). While the shape of the curve for any given mineral commodity may or may not be known, it is knowable since the geologic processes responsible for the curve's shape took place many years ago. In contrast, the factors governing how fast society moves up the curve and how the curve shifts over time are not only unknown but also unknowable.Using lithium as an example, this article shows that knowledge about the shape of the cumulative availability curve can by itself provide useful insights for some mineral commodities regarding the potential future threat of shortages due to depletion. Despite the inherent uncertainties surrounding the future growth in lithium demand as well as the uncertainties regarding the future cost-reducing effects of new production technologies, the shape of the lithium cumulative availability curve indicates that depletion is not likely to pose a serious problem over the rest of this century and well beyond.  相似文献   
72.
Australia has been a leading mining nation and its mines continue to attract substantial investment due to its strong mineral endowment, mining tradition and high skills base. In recent years Australian mining companies have been facing higher labour costs, which need to be offset by other savings. Automating mine-site machinery offers one potential source of such savings.Underground mines pioneered automated technology largely for safety and mine accessibility reasons and to reduce operating costs. Yet these operations now represent a much smaller portion of the total ore tonnes mined due to the changing mining techniques meaning larger lower grade deposits are becoming economic. It appears the future of mine automation will be directed by surface mining as this maturing technology finds further applications above ground and in the next decade large scale open pit automation trials gain more momentum.This paper assesses the implications of introducing driverless haul trucks in a typical large remote Australian open-pit mine. Such automation will save employee and associated costs, increase operational productive hours and ultimately will reduce mine site workforce numbers. While there will be fewer jobs per mine, with reduced costs and higher productivity some previously uneconomic mines may again be profitable.The social implications of greater mine site automation are the reduction in population of remote mining towns and a decrease in the lower skilled labour requirements for the mining sector. There will be an increase in fly-in fly-out mining operations and companies will establish remote control centres for automated mines in larger cities. This may decrease overall labour requirements and so reduce employment in the sector; therefore, the government should be mindful of implementing policies that ensure a fair return on the economic rent of mineral leases.  相似文献   
73.
Concentrations of natural radionuclides in imported mineral substances   总被引:1,自引:0,他引:1  
Levels of natural radionuclides, such as thorium-232 (232Th), radium-226 (226Ra) and potassium-40 (40K), were determined in about 2,000 samples of imported mineral substances using gamma spectrometry. The maximum concentration levels of 232Th, 226Ra and 40K were 1,260 +/- 54, 13,400 +/- 94 and 1,256 +/- 260 Bq kg(-1), respectively, in zirconium compounds. Due to relatively high concentrations of the above-mentioned radionuclides in some imported mineral substances, the National Radiation Protection Department (NRPD), as the competent authority, has established national limits (900 Bq kg(-1) for 232Th, 1800 Bq kg(-1) for 226Ra and 11,000 Bq kg(-1) for 40K), based on the external exposures, for general importation permits of these materials.  相似文献   
74.
我国石棉替代品生产、使用、危害及防护措施状况   总被引:2,自引:2,他引:2  
虽然石棉的用途广泛、价格低廉 ,但因其危害严重 ,存在着致癌问题 ,部分发达国家对石棉的使用进行了严格限制 ;为了降低石棉对人体健康的伤害 ,国际上大力提倡使用石棉替代品。针对我国石棉替代品使用的现状 ,重点对目前使用最多的石棉替代品 :玻璃棉、岩棉等的生产、使用、危害及其防护措施状况进行了概要的回顾和简单分析。  相似文献   
75.
曹霞 《自然资源学报》2010,25(8):1255-1266
"小矿"是"小型矿山"的简称,因规模小、投资少、见效快等特点在发展中国家普遍存在,是各国矿业和农村经济的重要组成部分。但同时,它又因浪费资源、破坏环境、安全事故频发等问题而受到国际社会的高度关注。然而,到目前为止,国内外对小矿尚无一个公认的概念。论文基于对现有"小矿"定义以及与小矿相关概念的细致比较,试图给小矿下一个定义,籍此为我国修订中的《矿产资源法》献计献策。笔者以为,小矿是"以谋生或营利为目的,采用简单或基础的采掘设备与技术,在有限的矿藏范围内从事某种矿产品采选活动的小规模、劳动密集型矿山企业。其中包括开采规模达到国家规定的小型矿山标准的小型矿山企业和开采规模在小型矿山上限1/10以下的小矿山企业(含零星个体采矿)。小矿是采矿业最基本的构成部门。"  相似文献   
76.
成钢  陈伟佳 《环境工程》2012,(Z1):223-227
羊毛吸声毡是一种新开发的绿色环保吸声材料,采用羊毛纺织工业弃用的粗羊毛制成。羊毛吸声毡具有优异的防火、声学和环保性能,在文化演艺建筑中得到了大量应用。  相似文献   
77.
本研究采用盆栽试验法,研究了赤红壤、砖红壤中矿物油对水稻、花生的生理生态影响和矿物油在土壤中的净化。研究结果表明:矿物油对第一季水稻生长发育影响不大,对第二季则表现出明显的抑制作用,低浓度矿物油对花生生长发育有促进作用,高浓度则对其起抑制作用;收获后,水稻各部分及水稻土,花生根及花生土油残留均与投油量呈极显著的直线正相关关系,油在作物根部最易积累;种植两季水稻后,油在赤红壤、砖红壤中的净化率分别为80%以上和50%左右。最后,根据上述研究确定了赤红壤、砖红壤的矿物油临界含量分别为270.90mg/kg和318.92mg/kg。   相似文献   
78.
A field study was carried out at six locations in the Lazio region (Central Italy) aimed at characterising atmospheric particulate matter (PM10 and PM2.5) from the point of view of the chemical composition and grain size distribution of the particles, the mixing properties of the atmosphere, the frequency and relevance of natural events. The combination of four different analytical techniques (ion chromatography, X-ray fluorescence and ICP for inorganic components, thermo-optical analysis for carbon compounds) yielded sound results in terms of characterisation of the air masses. During the first three months of the study (October–December 2004), many pollution events of natural (sea-salt or desert dust episodes) or anthropogenic nature were identified and characterised. More than 90% of the collected mass was identified by chemical analysis. The central role played by the mixing properties of the lower atmosphere when pollution events occurred was highlighted. The results show a major impact of primary anthropogenic pollutants on traffic stations and a homogeneous distribution of secondary pollutants over the regional area. An evaluation of the sources of PM and an identification of possible reliable tracers were obtained using a chemical fractionation procedure.  相似文献   
79.
贺力荃  肖罡  赵彤昕 《干旱环境监测》2007,21(3):166-168,172
针对羊毛脂较低的原料,采用絮凝沉淀-生物接触氧化工艺处理洗毛废水.本文介绍了该工艺的设计参数和运行情况.监测结果表明,其运行效果稳定,出水水质达到《污水综合排放标准》(GB 8978-1996)二级排放标准.  相似文献   
80.
Overseas mineral exploration and mining investment by Australian companies increased dramatically from the early 1990s until 1997. In the wake of the Asian economic crisis and lower commodity prices it declined somewhat in 1998 and 1999. Reflecting their international competitiveness, Australian resource companies were actively involved in projects in about eighty nations in 1999. This study assesses the extent of growth in exploration and mining operations, the distribution between large and small companies and the changing regional focus which has been occurring. It also reflects on some of the key influences on this development. These include a strong domestic finance sector, supporting mining services provision, technological competitiveness, a growing attractiveness of offshore locations and increasing structural impediments at home.  相似文献   
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