全文获取类型
收费全文 | 324篇 |
免费 | 31篇 |
国内免费 | 77篇 |
专业分类
安全科学 | 32篇 |
废物处理 | 3篇 |
环保管理 | 68篇 |
综合类 | 197篇 |
基础理论 | 21篇 |
环境理论 | 3篇 |
污染及防治 | 33篇 |
评价与监测 | 15篇 |
社会与环境 | 51篇 |
灾害及防治 | 9篇 |
出版年
2023年 | 19篇 |
2022年 | 18篇 |
2021年 | 17篇 |
2020年 | 25篇 |
2019年 | 22篇 |
2018年 | 11篇 |
2017年 | 17篇 |
2016年 | 23篇 |
2015年 | 19篇 |
2014年 | 8篇 |
2013年 | 43篇 |
2012年 | 19篇 |
2011年 | 30篇 |
2010年 | 19篇 |
2009年 | 15篇 |
2008年 | 8篇 |
2007年 | 21篇 |
2006年 | 14篇 |
2005年 | 18篇 |
2004年 | 11篇 |
2003年 | 6篇 |
2002年 | 9篇 |
2001年 | 7篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有432条查询结果,搜索用时 15 毫秒
341.
几种植物在生长过程中对人工湿地污水处理效果的影响 总被引:12,自引:0,他引:12
不同的植物及植物的不同生长阶段对人工湿地系统污水处理效果都有影响。对几种华南地区常见的湿地植物在其不同生长阶段处理污水的效果进行了研究,采用了不种植物的沙滤系统作对照。结果表明:(1)植物生长过程中,植物高度能反映污水处理效果总体上的变化;(2)在植物的生长过程中,各人工湿地系统污水处理能力总体上持续增强,各水质指标pH、DO、TN、NH3-N、NO3-N、TP和CODCr等均呈下降趋势,其中TP和CODCr呈逐步下降,pH、DO、TN、NH3-N、NO3-N则呈现锯齿形波动,但总体上仍是下降过程;(3)植物系统氮处理能力好于无植物沙滤系统,而对磷TP和CODCr的去除则恰好相反;(4)不同植物对人工湿地污水的处理效果影响不明显。研究结果对探讨人工湿地污水处理规律和植物在人工湿地中的作用提供了新的科学依据,并为指导人工湿地工程的运行提供了参考。 相似文献
342.
Nitrogen and phosphorus removal in pilot-scale anaerobic-anoxic
oxidation ditch system 总被引:1,自引:0,他引:1
To achieve high efficiency of nitrogen and phosphorus removal and to investigate the rule of simultaneous nitrification and denitrification phosphorus removal(SNDPR),a whole course of SNDPR damage and recovery was studied in a pilot-scale,anaerobicanoxic oxidation ditch(OD),where the volumes of anaerobic zone,anoxic zone,and ditches zone of the OD system were 7,21,and 280L,respectively.The reactor was fed with municipal wastewater with a flow rate of 336 L/d.The concept of simultaneous nitrification and denitrification (SND)rate(rSND) was put forward to quantify SND.The results indicate that:(1)high nitrogen and phosphorus removal efficiencies were achieved during the stable SND phase,total nitrogen (TN) and total phosphate(TP) removal rates were 80%and 85%,respectively;(2)when the system was aerated excessively,the stability of SND was damaged,and rSND dropped from 80% to 20%or less;(3)the natural logarithm of the ratio of NOx to MJ4 in the effluent had a linear correlation to oxidation-reduction potential (ORP);(4)when NO3- was less than 6 mg/L.high phosphorus removal efficiency could be achieved;(5)denitrifying phosphorus removal (DNPR) could take place in the anaerobic-anoxic OD system.The major innovation was that the SND rate was devised and quantified. 相似文献
343.
采集北京及周边6个城市春、夏、秋、冬这4个季节大气PM2.5样品,用离子色谱法测定其中的左旋葡聚糖(LG)、甘露聚糖(MN)和半乳聚糖(GT),对比这3种脱水聚糖与PM2.5及有机碳(OC)的浓度水平和时空分布特征,应用SPSS 24.0软件分析了数据间的显著性差异.结果表明, 6个城市PM2.5、OC和LG浓度水平的季节分布规律高度相似,呈现冬季>春季>秋季>夏季, 4个季节3种脱水聚糖的浓度水平有显著性差异.从空间角度分析3种脱水聚糖浓度水平,北京与天津、保定、石家庄无显著性差异,但北京与济南、郑州有显著性差异.根据6个城市的LG/MN和LG/(MN+GT)等浓度水平的比较,初步判断该区域PM2.5中的生物质燃烧源主要来源于农作物秸秆和硬木.春季的PM2.5污染过程中,北京、天津、石家庄和济南的左旋葡聚糖在PM2.5中的含量变化基本保持稳定,显示该污染过程受生物质燃烧排放的影响较弱. 相似文献
344.
国家环境保护模范城市考核指标体系共28项考核指标(集中供热率仅考核北方城市),其中11项指标以环境监测为基础。环境监测类指标是环保模范城市考核中定量考核的主要方面,也是在创模过程中容易出现问题的方面。笔者根据多年参与环保模范城市考核的体会,提出了各项指标的操作要点。 相似文献
345.
Jess Britton 《Local Environment》2019,24(7):595-609
ABSTRACTThe ability of smart cities to address multiple priorities is currently receiving a great deal of attention from governments, industry and academia; however, there are relatively few explorations of how smart cities will be enacted and the equity implications of various elements of the agenda. This paper aims to begin to address this by considering the case of smart meter data in Great Britain and reviewing the potential for public interest benefits to be realised at both a national and city-scale. In order to interrogate how societal benefits of smart metering might be enabled or constrained at different scales, both transition management approaches to understanding the intricacies of transforming socio-technical systems, and urban governance literatures which explore the problems in aligning “smart” and “sustainable” agendas, are engaged with. The case suggests that there is great potential for smart meter data to deliver public interest benefits and in doing so contribute to equity in energy transitions through promoting the accrual of benefits to collective rather than solely individual or commercial interests. Despite this, under the current smart metering framework city-scale actors are largely excluded from utilising smart metering data unless they partner with a large incumbent company. This suggests that the configuration of national smart metering arrangements could be further embedding a marketised approach to smart cities and demonstrates the complex interlinking of socio-political processes operating across multiple scales in energy transitions. 相似文献
346.
Kylie Soanes Michael Sievers Yung En Chee Nicholas S. G. Williams Manisha Bhardwaj Adrian J. Marshall Kirsten M. Parris 《Conservation biology》2019,33(2):300-306
Despite repeated calls to action, proposals for urban conservation are often met with surprise or scepticism. There remains a pervasive narrative in policy, practice, and the public psyche that urban environments, although useful for engaging people with nature or providing ecosystem services, are of little conservation value. We argue that the tendency to overlook the conservation value of urban environments stems from misconceptions about the ability of native species to persist within cities and towns and that this, in turn, hinders effective conservation action. However, recent scientific evidence shows that these assumptions do not always hold. Although it is generally true that increasing the size, quality, and connectivity of habitat patches will improve the probability that a species can persist, the inverse is not that small, degraded, or fragmented habitats found in urban environments are worthless. In light of these findings we propose updated messages that guide and inspire researchers, practitioners, and decision makers to undertake conservation action in urban environments: consider small spaces, recognize unconventional habitats, test creative solutions, and use science to minimize the impacts of future urban development. 相似文献
347.
以大连市北部的县级市瓦房店市、普兰店市和庄河市为研究区,引用2005年土地利用矢量数据,选用生态意义较明确的景观特征指数,对大连北三市土地利用景观格局及其生态环境效应进行比较分析。揭示土地利用景观格局对生态环境的影响。 相似文献
348.
文章扼要地介绍了内蒙古清洁生产的六个示范工程的进展 ,分析了内蒙古依赖资源比较优势的生产企业与生态保护和生态建设密切相依的特点 ,提出政府行为在推进清洁生产中的作用 相似文献
349.
Roger Mackett 《环境科学学报(英文版)》1999,11(3):334-338
1 ThenatureofurbantransportproblemsMostlargecitiesaroundtheworldaresufferingfromproblemscausedbytransport,includingcongestionandatmosphericpollution.Thesestemfromincreasingcarownershipanduse.Thecarenablesitsownerstoenjoyarangeofopportunities,moreandm… 相似文献
350.