全文获取类型
收费全文 | 4877篇 |
免费 | 620篇 |
国内免费 | 1386篇 |
专业分类
安全科学 | 436篇 |
废物处理 | 154篇 |
环保管理 | 574篇 |
综合类 | 3449篇 |
基础理论 | 550篇 |
环境理论 | 3篇 |
污染及防治 | 599篇 |
评价与监测 | 828篇 |
社会与环境 | 269篇 |
灾害及防治 | 21篇 |
出版年
2024年 | 22篇 |
2023年 | 136篇 |
2022年 | 187篇 |
2021年 | 234篇 |
2020年 | 237篇 |
2019年 | 208篇 |
2018年 | 217篇 |
2017年 | 266篇 |
2016年 | 318篇 |
2015年 | 330篇 |
2014年 | 318篇 |
2013年 | 404篇 |
2012年 | 385篇 |
2011年 | 468篇 |
2010年 | 254篇 |
2009年 | 253篇 |
2008年 | 236篇 |
2007年 | 304篇 |
2006年 | 312篇 |
2005年 | 242篇 |
2004年 | 215篇 |
2003年 | 273篇 |
2002年 | 207篇 |
2001年 | 198篇 |
2000年 | 168篇 |
1999年 | 109篇 |
1998年 | 81篇 |
1997年 | 65篇 |
1996年 | 57篇 |
1995年 | 36篇 |
1994年 | 33篇 |
1993年 | 17篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1990年 | 20篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 11篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有6883条查询结果,搜索用时 31 毫秒
941.
N. Anger B. Brouns J. Onigkeit 《Mitigation and Adaptation Strategies for Global Change》2009,14(5):379-398
We investigate the role of domestic allowance allocation and global emissions constraints for the carbon-market impacts of
linking the EU Emissions Trading Scheme (ETS) internationally. Employing a quantitative simulation model of the global carbon
market, we find that the economic benefits from connecting the European ETS to emerging non-EU schemes strongly depend on
the regional allowance allocation of the linking participants: In a world of moderate carbon constraints, an economically
efficient regional allowance allocation induces a much stronger fall in total compliance costs than a sub-optimal (i.e. too
high) domestic allocation of emissions permits. However, a more efficient (i.e. stricter) allocation shifts abatement efforts
and compliance costs to energy-intensive industries which are covered by the domestic ETS. We further find that committing
to ambitious global emissions reduction targets (compatible with stabilizing CO2 concentrations at 450 ppm) induces much stronger regional abatement efforts and substantially higher compliance costs for
the abating regions. In such an ambitious climate policy regime, an efficient domestic allocation of allowances is even more
important from an economic perspective: Here, linking emissions trading schemes diminishes the associated compliance costs
on the largest scale.
相似文献
J. OnigkeitEmail: |
942.
C. Streck A. Tuerk B. Schlamadinger 《Mitigation and Adaptation Strategies for Global Change》2009,14(5):455-463
An important aspect in the linking of different emissions trading schemes is the degree to which these systems allow (or ban)
external offset project categories. The EU Emission Trading Scheme (EU ETS) currently allows the use of credits from energy
and industry projects developed under the Kyoto Protocol’s Joint Implementation (JI) and Clean Development Mechanism (CDM)
but excludes the use of carbon credits from forestry projects for compliance in the EU ETS. Forestry credits generated by
the CDM have a limited lifetime and expire at the end of a project’s crediting period, or earlier if the carbon stock for
which the credits have been issued ceases to exist. According to the recently adopted amendment of the EU ETS Directive forestry
credits will remain to be excluded until 2020. The present article reviews how the New South Wales Greenhouse Gas Abatement
Scheme (Australia), the Regional Greenhouse Gas Initiative (US) and the voluntary scheme of the Chicago Climate Exchange integrate
forestry offsets into the respective system and how they deal with the risk of losing stored and credited biomass. By comparing
the results of different scenarios this article shows how differences in the treatment of forestry offsets could impact the
efforts to link various emission trading systems in future.
相似文献
A. TuerkEmail: |
943.
Alexander Golub Jos Cozijnsen Annie Petsonk 《Mitigation and Adaptation Strategies for Global Change》2009,14(5):433-453
This article examines possibilities for linkage between the European Union Emissions Trading System (EU ETS) and Russia, with
a view to enhancing cooperation on a broader scale than the project-based approaches that have been tested thus far. Three
paths for possible EU-Russia linkage are presented by which the Russian Assigned Amount under the Kyoto Protocol can be greened
in order to stimulate emissions trading: 1. Joint implementation—reductions earned via individual projects in Russia; 2. Greened
allowances or green investment schemes; and 3. Linked cap-and-trade systems, in which a Russian domestic emissions trading
system would link with the European Union Emissions Trading System. The authors conclude that the third option, emissions
trading through linked domestic emissions trading systems, offers the best opportunities at the lowest transaction costs.
The authors discuss useful innovative instruments like call options and slip level arrangements on government-to-government
and business-to-business levels.
相似文献
Annie PetsonkEmail: |
944.
特定岸坡生态系统去除水源中微量有机物实验研究 总被引:1,自引:0,他引:1
水源地长期污染严重,微量有机物检出率增加,水质安全性下降,以及岸坡传统硬质化护砌导致生态恶化,为此提出以新型环保材料生态混凝土构建特定岸坡生态系统改善水源水质的研究方法.中试实验结果表明,停留时间为6 d时,水中阿特拉津、邻苯二甲酸二甲酯、邻苯二甲酸二(2-乙基己基)酯、邻苯二甲酸二乙酯、邻苯二甲酸二丁酯的去除率分别为70.5%、57.7%、72.4%、62.4%和45.1%,水样有机物图谱峰数与黄浦江原水相比减少23个,峰总面积降低36.8%;相同条件下对照水库(岸坡硬质护砌),5种微量有机物的去除率仅为40.2%、42.9%、54.8%、52.0%和16.2%.以生态混凝土为载体构建的水源地特定岸坡生态系统在微生物和绿色植物等多因素协同作用下,使水中微量有机物去除效果明显,对改善水源水质和生态修复具有积极意义. 相似文献
945.
An attempt has been made to produce stable water–diesel emulsion with optimal formulation and process parameters and to evaluate the performance and emission characteristics of diesel engine using this stable water–diesel emulsion. A total of 54 samples were prepared with varying water/diesel ratio, surfactant amount and stirring speed and water separation was recorded after 24 and 48 hr of emulsification. The recorded data were used in artificial neural network (ANN)-particle swarm optimization (PSO) technique to find the optimal parameters to produce water–diesel emulsion for engine testing. The predicted optimal parameters were found as 20% water to diesel ratio, 0.9% surfactant and 2200 rpm of stirrer for a water separation of 14.33% in one day with a variation of 6.54% against the actual value of water separation. Water–diesel emulsion fuel exhibited similar fuel properties as base fuel. The peak cylinder gas pressure, peak pressure rise rate and peak heat release rate for water–diesel were found higher as compared to diesel at medium to full engine loads. The improved air-fuel mixing in water–diesel emulsion enhanced brake thermal efficiency (BTE) of engine. The absorption of heat by water droplets present in water–diesel emulsion led to reduced exhaust gas temperature (EGT). With water–diesel emulsion fuel, the mean carbon monoxide (CO), unburned hydrocarbon and oxides of nitrogen (NOx) emissions reduced by 8.80, 39.60, and 26.11%, respectively as compared to diesel. 相似文献
946.
Chandra Prakash 《International Journal of Green Energy》2019,16(7):551-572
The performance characteristics of a solar air heater can effectively be improved by providing artificial roughness in the form of protrusions and dimples of various shapes, sizes, and orientations on the underside of heated surface. An extensive literature review on artificial roughness elements has been carried and the correlations developed for heat transfer and friction factor for roughened solar air collector have been discussed and presented in this paper. The performance parameter has also been computed and compared with various kinds and shapes of roughness geometries using correlations developed by various investigators. The optimum values of the roughness parameters obtained by several investigators have also been discussed. 相似文献
947.
作为全球气候治理的重要手段,碳排放交易制度受到了广泛的关注与讨论。基于此,本文采用我国2010-2016年城市面板数据,运用非参数方法构建方向性环境距离函数测算了2009-2015年城市减排的机会成本,计算结果显示,试点地区与非试点地区的碳排放的机会成本整体表现为上升的趋势,且试点地区的碳排放的机会成本总体低于非试点地区。在测算城市减排机会成本的基础上,运用双重差分法来检验碳排放交易制度的有效性。经检验发现:碳排放交易制度有利于降低城市减排的机会成本,然而由于碳排放交易制度还存在碳排放权初始分配制度缺失、碳排放交易制度的定价机制扭曲等问题,因此其对降低城市减排的机会成本作用较小,并且进一步通过对政策时间趋势的分析得出政策效应随时间推移而逐渐减弱。 相似文献
948.
利用2013年5月20日-6月20日成都市区7个环境质量监测站点可吸入颗粒物(PM10)、细颗粒物(PM2.5)、SO2、NO2、CO和臭氧的实测资料及地面气象观测资料,对成都举办财富全球论坛期间及前后的空气质量变化特征和成因进行分析.结果表明,由于市政府采取交通管制措施,使机动车尾气排放的NO2浓度与财富论坛前后相比降幅达27.2%;财富论坛期间臭氧前体物质浓度的降低,使地面臭氧日均浓度在相同太阳日辐射值下与财富论坛前后相比较低;对城区扬尘控制和周边重污染企业限产停产,分别对PM10和SO2的排放起到了明显的削减作用;后向轨迹分析表明市区SO2浓度累积与来自东南部低空的气团有关.当相对湿度小于60%时颗粒物容易吸湿增长,而当相对湿度大于60%时降雨概率增大,颗粒物容易被清除.综合分析,成都市区财富论坛期间空气质量改善是政府减排举措的有效实施和较好的气象条件共同作用的结果. 相似文献
949.
采用液相色谱法对环境空气中的酰胺类化合物进行了测定,优化了实验条件.液相色谱采用C18柱,以水∶乙腈(93∶7)为流动相,流速为0.5 mL/min,柱温:30℃,紫外检测器波长198 nm.二甲基甲酰胺的检出限为0.006 3 mg/m3,三个不同浓度的加标回收率为95.0%~98.3%;二甲基乙酰胺的检出限为0.009 2 mg/m3,三个不同浓度的加标回收率为91.3%~98.2%;丙烯酰胺的检出限为0.004 9 mg/m3,三个不同浓度的加标回收率为96.3%~102%. 相似文献
950.