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   137篇
  免费   2篇
  国内免费   7篇
安全科学   12篇
废物处理   2篇
环保管理   30篇
综合类   28篇
基础理论   33篇
污染及防治   23篇
评价与监测   13篇
社会与环境   4篇
灾害及防治   1篇
  2022年   4篇
  2020年   3篇
  2019年   4篇
  2018年   1篇
  2017年   1篇
  2016年   2篇
  2015年   5篇
  2014年   6篇
  2013年   10篇
  2012年   5篇
  2011年   11篇
  2010年   4篇
  2009年   17篇
  2008年   9篇
  2007年   9篇
  2006年   7篇
  2005年   6篇
  2004年   3篇
  2003年   5篇
  2002年   6篇
  2001年   2篇
  2000年   2篇
  1999年   3篇
  1998年   3篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1992年   1篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1982年   1篇
  1980年   1篇
  1977年   1篇
排序方式: 共有146条查询结果,搜索用时 15 毫秒
71.
N. Hamidi  M. Meftahi 《Safety Science》2012,50(5):1180-1189
Nowadays, with implementation of management systems and environment management and due to the influence of safety and health issues on working processes, organizations have also sought to acquire health and safety management systems. This study which aims to examine the influence of integrated management system on safety and productivity indices has retrospective experimental nature. It was conducted in Cement Factories in which three systems are used: quality, environment and safety systems. The collected data were: accident reports and the investigation of events in 6 years during 2005-2010 (3 years before and 3 years after the implementation of the system). The safety indices that used in this study are: IFR, ISR, FSI, and Safe T. Score. Then, the data analyzed with the T-test, mean and standard deviation. The results showed a significant difference between various safety indices before and after the implementation. The examination of production indices such as increasing rate of productivity and production indicates the influence of these systems on production and productivity indices. The results have showed that the safety system existence cannot ensure productivity increase. Indices definition can be helpful for the safety system effectiveness and system continual improvement. It is important to say that there might be various indices definition in different industries.  相似文献   
72.
Successful modeling of liquid and air flow and hence designing of liquid and air addition systems in the landfills are constrained by the lack of key parameters of unsaturated hydraulic properties of municipal solid waste (MSW), which are strongly dependent on the depth of burial and the degree of decomposition. In this study, water retention curves (WRC) of MSW are measured using pressure plate method on samples repacked according to the in situ unit weight measured during borehole sampling, representing the MSW in shallow, middle, and deep layers. The measured WRC of MSW is well-reproduced by the van Genuchten-Mualem model, and is used to predict the unsaturated hydraulic properties of MSW, including water retention characteristics and unsaturated hydraulic conductivity. The estimated model parameters are consistent with other studies, suggesting that the pressure plate method yields reproducible results. As the landfill depth and age increase, the overburden pressure, the highly decomposed organic matter and finer pore space increase, hence the capillary pressure increases, causing increases in air-entry values, field capacity and residual water content, and decreases in steepness of WRC and saturated water content. The unsaturated hydraulic properties of MSW undergo changes with landfill depth and age, showing more silt loam-like properties as the landfill age increases.  相似文献   
73.
对矿井风流热交换计算常用的参数之一即显热比的变化规律进行了理论分析。定量分析了显热比与通风时间 (巷道壁面温度 )、巷道壁面的湿度系数、风流的相对湿度等参数之间的关系。通风开始后 ,壁面温度随着暴露时间的增长而降低 ,显热比也随通风时间增长而降低。显热比随巷道壁面湿度系数的增加而下降 ;随着风流相对湿度的增加 ,显热比增加  相似文献   
74.
建立包含压力-状态-响应要素的指标体系,采用基于熵权的模糊数学评价方法,运用相对隶属度算法评价在快速城市化胁迫下(2000~2007年)连云港市入海河流(以蔷薇河为例)相对健康程度,该方法避免了主观判断河流环境健康标准的不确定性.评价结果表明2000~2007年,连云港市蔷薇河相对健康整体大致呈下降趋势,最优年为200...  相似文献   
75.
采用吹扫捕集-气相色谱/质谱法,通过统计全国多家实验室的测定数据和实际样品测试两种方法,对水中苯、甲苯、乙苯、间/对二甲苯、邻二甲苯、苯乙烯和异丙苯8种苯系物的平行样测定相对偏差、空白加标回收率及实际样品加标回收率3个质控指标进行了研究,分别给出每种苯系物的质控指标评价标准,提出其平行样测定相对偏差为6.5% ~13....  相似文献   
76.
几种工业废水可生化性判定指标的验证与评价   总被引:2,自引:0,他引:2       下载免费PDF全文
测定了几种工业废水的可生化性指标BOD5/COD比值和相对耗氧速率,根据模拟生物氧化塘的动态运行试验结果,提出以耗氧速率(R%)作为可生化性的判定指标,它比BOD5/COD比值测定快速,方法简便,更接近实际,并得出两个指标与生物塘COD去除率之间相关性的线性回归方程,为选择废水生物塘处理方案、预估其对COD的去除效率提供了理论依据。   相似文献   
77.
Over the past two decades, the combination of molecular and field methods has revealed considerable variation in the level of extrapair fertilizations among socially monogamous birds. Models predicting extrapair young range in scale from a single population to multiple Orders, and there is no single, unifying theory for these reproductive tactics. We investigated proximate explanations of extrapair fertilizations in two subspecies of the swamp sparrow, Melospiza georgiana georgiana and Melospiza georgiana nigrescens, across a range of social and environmental conditions. The presence of extrapair young was best predicted by the size of two male plumage badges (one correlated with parental care and one with territorial aggression) relative to the badge size of their immediate neighbors, the interaction of these two measures, mean territory size, and the maximum size of the aggression badge among neighbors. The size of the male’s parental care badge (relative to neighbors) was negatively correlated with the probability of lost paternity. The relative size of the aggression badge was positively correlated with the presence of extrapair young when the parental care badge was small and negatively correlated when the badge was large. Controlling for these crown measures, males with larger territories were less likely to suffer losses in paternity. There was no effect of breeding density, breeding synchrony, their interaction, subspecies, or weather during the fertile period on the presence of extrapair young. These results suggest that female preference for males that provide more parental care (or preference for genes that convey this trait) plays a dominant role in extrapair interactions among swamp sparrows. Models based on female assessments of relative mate quality offer a promising explanation of patterns in extrapair fertilizations among bird species.  相似文献   
78.
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   
79.
Buteo regalis ), northern harriers (Circus cyaneus), burrowing owls (Athene cunicularia), and short-eared owls (Asio flammeus) inside and outside a military training site in the Snake River Birds of Prey National Conservation Area, southwestern Idaho. The Orchard Training Area is used primarily for armored vehicle training and artillery firing by the Idaho Army National Guard. Relative abundance of nesting pairs inside and outside the training site was not significantly different from 1991 to 1993 but was significantly higher on the training site in 1994 (P ≤ 0.03). Nesting success varied among years but was not significantly different inside and outside the training site (P > 0.26). In 1994, short-eared owl and burrowing owl nests were significantly closer to firing ranges used early in the spring before owls laid eggs than were random points (P < 0.001). In 1993, distances from occupied burrowing owl nests to firing ranges used early in the year were similar to those from random points to the same firing ranges (P = 0.16). Military activity contributed to some nesting failures from 1992 to 1994, but some pairs nested successfully near military activity.  相似文献   
80.
This paper describes a more compelling case for industry to promote the non-energy benefits of energy efficiency investments. We do this in two ways to actively appeal to chief executive officers (CEOs) and chief financial officers (CFOs) primary responsibility: to enhance shareholder value. First, we describe the use of a project-by-project corporate financial analysis approach to quantify a broader range of productivity benefits that stem from investments in energy-efficient technologies, including waste reduction and pollution prevention. Second, and perhaps just as important, we present such information in corporate financial terms. These standard, widely-accepted analysis procedures are more credible to industry than the economic modeling done in the past because they are structured in the same way corporate financial analysts perform discounted cashflow investment analyses on individual projects. Case studies including such financial analyses, which quantify both energy and non-energy benefits from investments in energy-efficient technologies, are presented. Experience shows that energy efficiency projects’ non-energy benefits often exceed the value of energy savings, so energy savings should be viewed more correctly as part of the total benefits, rather than the focus of the results. Quantifying the total benefits of energy efficiency projects helps companies understand the financial opportunities of investments in energy-efficient technologies. Making a case for investing in energy-efficient technologies based on energy savings alone has not always proven successful. Evidence suggests, however, that industrial decision makers will understand energy efficiency investments as part of a broader set of parameters that affect company productivity and profitability.  相似文献   
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