全文获取类型
收费全文 | 896篇 |
免费 | 7篇 |
国内免费 | 109篇 |
专业分类
安全科学 | 50篇 |
废物处理 | 23篇 |
环保管理 | 177篇 |
综合类 | 325篇 |
基础理论 | 167篇 |
环境理论 | 1篇 |
污染及防治 | 183篇 |
评价与监测 | 48篇 |
社会与环境 | 38篇 |
出版年
2023年 | 24篇 |
2022年 | 26篇 |
2021年 | 16篇 |
2020年 | 23篇 |
2019年 | 29篇 |
2018年 | 18篇 |
2017年 | 26篇 |
2016年 | 39篇 |
2015年 | 47篇 |
2014年 | 44篇 |
2013年 | 62篇 |
2012年 | 37篇 |
2011年 | 107篇 |
2010年 | 49篇 |
2009年 | 74篇 |
2008年 | 77篇 |
2007年 | 73篇 |
2006年 | 34篇 |
2005年 | 32篇 |
2004年 | 20篇 |
2003年 | 19篇 |
2002年 | 19篇 |
2001年 | 19篇 |
2000年 | 14篇 |
1999年 | 7篇 |
1998年 | 17篇 |
1997年 | 11篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 2篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有1012条查询结果,搜索用时 15 毫秒
971.
Kazuya Goto Hiromichi Okabe Firoz Alam Chowdhury Shinkichi Shimizu Yuichi Fujioka Masami Onoda 《International Journal of Greenhouse Gas Control》2011,5(5):1214-1219
In order to establish energy-saving technology for CO2 capture from blast furnace gas, novel absorbents were developed in the laboratory and evaluated at a 1 tCO2/d test plant. At first, CO2 absorption and desorption behaviors of single-component amine solvents for simulated blast furnace gas (CO2/N2 = 20%/80%) were investigated through a screening test using a small scrubbing bottle. These amine solvents were additionally analyzed using nuclear magnetic resonance (13C NMR) spectroscopy and reaction calorimetry. The results of the laboratory experiments showed that there was a trade-off between absorption rate and enthalpy of absorption but some absorbents had unique features. For example, 2-isopropylaminoethanol (IPAE) had high absorption rate and small enthalpy of absorption. Then, new IPAE-based amine solvents (RITE solvents: RITE-A and RITE-B) were formulated and evaluated at the 1 tCO2/d test plant. CO2 regeneration energies of the RITE solvents were 3.3 and 3.1 GJ/tCO2, respectively. With certain process conditions and plant specifications optimized, RITE-B was estimated to have the potential to achieve 2.5 GJ/tCO2. 相似文献
972.
Fragmentation drives tropical forest fragments to early successional states: A modelling study for Brazilian Atlantic forests 总被引:1,自引:0,他引:1
Land use leads to massive habitat destruction and fragmentation in tropical forests. Despite its global dimensions the effects of fragmentation on ecosystem dynamics are not well understood due to the complexity of the problem. We present a simulation analysis performed by the individual-based model FORMIND. The model was applied to the Brazilian Atlantic Forest, one of the world's biodiversity hot spots, at the Plateau of São Paulo. This study investigates the long-term effects of fragmentation processes on structure and dynamics of different sized remnant tropical forest fragments (1-100 ha) at community and plant functional type (PFT) level. We disentangle the interplay of single effects of different key fragmentation processes (edge mortality, increased mortality of large trees, local seed loss and external seed rain) using simulation experiments in a full factorial design.Our analysis reveals that particularly small forest fragments below 25 ha suffer substantial structural changes, biomass and biodiversity loss in the long term. At community level biomass is reduced up to 60%. Two thirds of the mid- and late-successional species groups, especially shade-tolerant (late successional climax) species groups are prone of extinction in small fragments. The shade-tolerant species groups were most strongly affected; its tree number was reduced more than 60% mainly by increased edge mortality. This process proved to be the most powerful of those investigated, explaining alone more than 80% of the changes observed for this group. External seed rain was able to compensate approximately 30% of the observed fragmentation effects for shade-tolerant species.Our results suggest that tropical forest fragments will suffer strong structural changes in the long term, leading to tree species impoverishment. They may reach a new equilibrium with a substantially reduced subset of the initial species pool, and are driven towards an earlier successional state. The natural regeneration potential of a landscape scattered with forest fragments appears to be limited, as external seed rain is not able to fully compensate for the observed fragmentation-induced changes. Our findings suggest basic recommendations for the management of fragmented tropical forest landscapes. 相似文献
973.
Stefan Giljum Eva BurgerFriedrich Hinterberger Stephan LutterMartin Bruckner 《Resources, Conservation and Recycling》2011,55(3):300-308
Many of today's most urgent environmental problems arise from increasing volumes of worldwide production and consumption and the associated use of natural resources, including renewable and non-renewable raw materials, energy, water and land. Solid indicators to measure different dimensions of anthropogenic resource use are essential for designing appropriate policy measures for a sustainable management of these resources. Based on a brief review of the current state of the art of resource use indicators, this paper suggests a new set of complementary resource use indicators, combining existing measures for resource use. The suggested indicator set covers the core resource input categories of materials, water and land area and includes the output category of greenhouse gas emissions. This set can be applied consistently from the micro level of products and companies up to the macro level of countries and world regions. All suggested indicators take a life-cycle wide perspective on production and consumption activities. This set of indicators deals with the issue of the overall scale of the human production and consumption system. It can be regarded as the general indicator framework, based on which more specific indicators, for example, on different environmental impacts related to natural resource use, can be calculated. 相似文献
974.
再生水资源是水资源的一种特殊形式,它的价格是影响污水回用的重要因素之一。再生水价格有多种形式,其中甲醇的投加是一笔不小的成本。以污水处理厂二级出水为水源进行深度处理以实现污水资源化的过程中,存在着总氮含量高、有机物含量低的水质特点。再生水处理中反硝化阶段需要有机物,也就是碳源。碳源影响脱氮效果,投加甲醇为外碳源可以促进反硝化水平。 相似文献
975.
通过分析2002~2011年间陕西省建设用地和碳排放的变化,基于LMDI模型分解方法,探讨了10年间建设用地变化对碳排放增长的影响。结果表明:研究时序内,陕西省建设用地和碳排放量均呈增长态势,建设用地年扩展率1.25%,碳排放年均增长8.84%,建设用地变化与碳排放量正向效应显著,建设用地对碳排放的贡献度为12.36%,对建设用地采取总量控制原则,能有效控制碳排放量,对陕西省实现"十二五"期间碳减排目标具有重大意义。 相似文献
976.
977.
黄土丘陵区刺槐林深层土壤有机碳矿化特征初探 总被引:9,自引:3,他引:6
土壤剖面100 cm以下的深层土壤有机碳储量在土壤碳储量中占有很大比例,研究深层土壤有机碳矿化特征以揭示其稳定性,可为深层土壤碳汇认证提供依据.本文以浅层土壤(0~100 cm)为对照,模拟深层土壤温度和水分条件(温度15℃、土壤含水量8%),研究了黄土丘陵区刺槐林深层土壤(100~400 cm)有机碳矿化特征.结果表明:①土壤有机碳总矿化量随着土壤深度增加呈下降趋势,亚深层(100~200 cm)、深层(200~400 cm)有机碳总矿化量分别占浅层(0~100 cm)土壤总矿化量的88.1%和67.8%;②亚深层、深层与浅层土壤有机碳矿化过程相似,分为3个阶段.快速分解阶段:亚深层、深层(0~10 d)的矿化量占总矿化量的比值约为浅层(0~17 d)的50%;缓慢分解阶段:亚深层、深层(11~45 d)的矿化量占总矿化量的比值约为浅层(18~45 d)的150%;相对稳定阶段:3个层次(46~62 d)矿化量占总矿化量的比值无明显差异.③浅层、亚深层、深层土壤有机碳矿化率差异不显著(P>0.05),有机碳稳定性基本一致.研究结果反映了深层土壤有机碳也参与土壤碳循环,在评估黄土丘陵区土壤固碳效应时应充分考虑深层土壤有机碳的变化. 相似文献
978.
This paper builds on and extends previous research to contribute to ongoing discussion on the use of resource and carbon accounting tools in regional policy making. The Northern Visions project has produced the first evidence-based footpath setting out the actions that need to be taken to achieve the step changes in the Ecological and Carbon Footprint of Northern Ireland. A range of policies and strategies were evaluated using the Resources and Energy Analysis Programme. The analysis provided the first regional evidence base that current sustainable development policy commitments would not lead to the necessary reductions in either the Ecological Footprint or carbon dioxide emissions. Building on previous applications of Ecological Footprint analysis in regional policy making, the research has demonstrated that there is a valuable role for Ecological and Carbon Footprint Analysis in policy appraisal. The use of Ecological and Carbon Footprint Analysis in regional policy making has been evaluated and recommendations made on ongoing methodological development. The authors hope that the research can provide insights for the ongoing use Ecological and Carbon Footprint Analysis in regional policy making and help set out the priorities for research to support this important policy area. 相似文献
979.
ABSTRACTThis paper interrogates the impact of policy events on the efficiency of carbon market in China. The analysis covers five piloting emission trading schemes (Beijing, Shanghai, Guangdong, Shenzhen and Hubei), particularly focusing on Guangdong pilot for its weak form efficiency and the richness of policy events. Twenty-five policy events between 2014 and 2016 are categorized into seven groups. The efficiency test indicates that only Guangdong ETS has reached weak form efficiency. After exploring the policy events occurred in Guangdong ETS, it finds that although a clear long-term climate policy has been set up over the country, China’s carbon market still has a conservative risk appetite and its governing institutions still needs further development. The policy makers need to be aware of and avoid the negative impacts of policy events to the market evolvement, by introducing effective consultancy process with the stakeholders and nurturing market expectations in the long run. We also find that events like allowance auctions have considerably less impacts than previously expected and argue that auction approach should be considered a preferable option over a free allocation system in the future policy design. 相似文献
980.
Studies dealing with media coverage of climate change have increased steadily over the last decade or so, alongside the media coverage of climate change itself. This article aims to contribute to this growing literature on two levels: to deepen understanding of distinctive patterns of language use across nations speaking a common language and to demonstrate the usefulness of a new approach for finding such patterns. Articles in The (London) Times and the New York Times, published between 2000 and 2009, were analyzed using methods related to computational linguistics. Results show that the US seemingly still constructs climate change as a problem, whereas the UK focuses on finding solutions for the (established) problem of climate change. This linguistic and conceptual gap may hamper mutual understanding and the crafting of global climate change mitigation policies. 相似文献