全文获取类型
收费全文 | 3410篇 |
免费 | 291篇 |
国内免费 | 364篇 |
专业分类
安全科学 | 606篇 |
废物处理 | 131篇 |
环保管理 | 820篇 |
综合类 | 1495篇 |
基础理论 | 327篇 |
环境理论 | 19篇 |
污染及防治 | 140篇 |
评价与监测 | 64篇 |
社会与环境 | 396篇 |
灾害及防治 | 67篇 |
出版年
2024年 | 23篇 |
2023年 | 85篇 |
2022年 | 86篇 |
2021年 | 123篇 |
2020年 | 145篇 |
2019年 | 123篇 |
2018年 | 119篇 |
2017年 | 183篇 |
2016年 | 212篇 |
2015年 | 187篇 |
2014年 | 177篇 |
2013年 | 334篇 |
2012年 | 283篇 |
2011年 | 343篇 |
2010年 | 225篇 |
2009年 | 177篇 |
2008年 | 140篇 |
2007年 | 180篇 |
2006年 | 147篇 |
2005年 | 108篇 |
2004年 | 77篇 |
2003年 | 78篇 |
2002年 | 61篇 |
2001年 | 60篇 |
2000年 | 56篇 |
1999年 | 59篇 |
1998年 | 32篇 |
1997年 | 26篇 |
1996年 | 26篇 |
1995年 | 18篇 |
1994年 | 33篇 |
1993年 | 12篇 |
1992年 | 13篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1974年 | 3篇 |
排序方式: 共有4065条查询结果,搜索用时 296 毫秒
641.
642.
介绍了新型电除尘节能技术的原理及技术特点,以及该节能技术在山西某热电公司1、2号炉220MW机组电除尘器上的改造与应用情况。 相似文献
643.
Embodied energy and emergy evaluation of a typical biodiesel production chain in China 总被引:1,自引:0,他引:1
L.P. JuB. Chen 《Ecological modelling》2011,222(14):2385-2392
Biodiesel from non-grain feedstock has been considered as one of the proper substitutes for fossil fuels associated with a series of activities emerging in China in order to meet the resource shortage and develop the energy crops. This paper presents an ecological accounting framework based on embodied energy, emergy, and CO2 emission for the whole production chain of biodiesel made from Jatropha curcas L. (JCL) oil. The energy and materials invested in and CO2 emission from the whole process, including cropping, transportation, extraction, and production, are accounted and calculated. Also, EmCO2, the ratio of real CO2 released to the emergy-based sustainability indicator per joule biodiesel, is proposed in this paper to present a new goal function for low-carbon system optimization. Finally, the results are compared with those of the bioethanol (wheat) production in Henan Province, China, and bioethanol (corn) production in Italy in view of the indices of embodied energy, emergy and CO2 emissions and EmCO2. 相似文献
644.
CO2 capture and storage from a bioethanol plant: Carbon and energy footprint and economic assessment
A. Laude O. Ricci G. Bureau J. Royer-Adnot A. Fabbri 《International Journal of Greenhouse Gas Control》2011,5(5):1220-1231
Biomass energy and carbon capture and storage (BECCS) can lead to a net removal of atmospheric CO2. This paper investigates environmental and economic performances of CCS retrofit applied to two mid-sized refineries producing ethanol from sugar beets. Located in the Region Centre France, each refinery has two major CO2 sources: fermentation and cogeneration units. “carbon and energy footprint” (CEF) and “discounted cash flow” (DCF) analyses show that such a project could be a good opportunity for CCS early deployment. CCS retrofit on fermentation only with natural gas fired cogeneration improves CEF of ethanol production and consumption by 60% without increasing much the non renewable energy consumption. CCS retrofit on fermentation and natural gas fired cogeneration is even more appealing by decreasing of 115% CO2 emissions, while increasing non renewable energy consumption by 40%. DCF shows that significant project rates of return can be achieved for such small sources if both a stringent carbon policy and direct subsidies corresponding to 25% of necessary investment are assumed. We also underlined that transport and storage cost dilution can be realistically achieved by clustering emissions from various plants located in the same area. On a single plant basis, increasing ethanol production can also produce strong economies of scale. 相似文献
645.
646.
Hailong Li Øivind Wilhelmsen Yuexia Lv Weilong Wang Jinyue Yan 《International Journal of Greenhouse Gas Control》2011,5(5):1119-1139
Accurate experimental data on the thermo-physical properties of CO2-mixtures are pre-requisites for development of more accurate models and hence, more precise design of CO2 capture and storage (CCS) processes. A literature survey was conducted on both the available experimental data and the theoretical models associated with the transport properties of CO2-mixtures within the operation windows of CCS. Gaps were identified between the available knowledge and requirements of the system design and operation. For the experimental gas-phase measurements, there are no available data about any transport properties of CO2/H2S, CO2/COS and CO2/NH3; and except for CO2/H2O(/NaCl) and CO2/amine/H2O mixtures, there are no available measurements regarding the transport properties of any liquid-phase mixtures. In the prediction of gas-phase viscosities using Chapman–Enskog theory, deviations are typically <2% at atmospheric pressure and moderate temperatures. The deviations increase with increasing temperatures and pressures. Using both the Rigorous Kinetic Theory (RKT) and empirical models in the prediction of gas-phase thermal conductivities, typical deviations are 2.2–9%. Comparison of popular empirical models for estimation of gas-phase diffusion coefficients with newer experimental data for CO2/H2O shows deviations of up to 20%. For many mixtures relevant for CCS, the diffusion coefficient models based on the RKT show predictions within the experimental uncertainty. Typical reported deviations of the CO2/H2O system using empirical models are below 3% for the viscosity and the thermal conductivity and between 5 and 20% for the diffusion coefficients. The research community knows little about the effect of other impurities in liquid CO2 than water, and this is an important area to focus in future work. 相似文献
647.
Using dynamic energy budget (DEB) theory, this paper explores the potential of excess and harmful radiation, notably UV, to cause changes in performance and, ultimately, bleaching in scleractinian corals for a range of ambient nitrogen and (beneficial) photosynthetically active radiation levels. Two negative impacts of radiation are considered: a reduction in the capacity of the symbiont to generate energy through photosynthesis (defined in this paper as photoinhibition); an increase in the costs for the symbiont to remain viable due to repair of damage (defined in this paper as photodamage). Model predictions indicate that although both types of impact reduce the growth potential of host and symbiont, photoinhibition predominantly affects host features, except at very low ambient nitrogen levels, under which conditions the severity of nitrogen limitation is so strong that a reduction in photosynthetic rates due to photoinhibition has minimal impact. In steady state, photoinhibition leads to a reduction in host biomass, and an increase in symbiont density, implying that photoinhibition (as defined in this paper) is unlikely to cause bleaching. In contrast, the impact of photodamage is mostly affecting symbiont features, including a decline in symbiont density. Thus, photodamage may contribute to coral bleaching. Furthermore, the model predicts that, with both photoinhibition and photodamage, an increasing ratio of harmful to beneficial radiation accelerates the suppression of growth rates of symbiont and host, implying that coral health deteriorates progressively faster with increasing harmful radiation, such as UVb. 相似文献
648.
人工湿地植物生物质资源能源化利用潜力评估 总被引:5,自引:0,他引:5
通过测定不同人工湿地植物的纤维素组分和热值,并采用NaOH–酶解工艺研究不同人工湿地植物水解液组分,对在人工湿地技术体系中起重要作用的湿地植物能源化利用潜力进行系统评估.结果显示,15种人工湿地植物的纤维素含量在19.78%~36.9%之间,半纤维素含量在4.51%~19.67%之间,木质素含量在10.79%~20.47%之间,具有与玉米秸秆相当的热值,其热值在14.002~17.839 MJ/kg之间.在NaOH–酶解工艺条件下,不同人工湿地植物水解液中存在5种糖类组分,主要为葡萄糖和木糖.研究表明,人工湿地植物是一种较好的生物质资源,可通过生物质固体成型燃料技术、沼气技术和燃料乙醇技术加以利用,进而建立人工湿地植物生物质资源能源化藕联利用模式.图2表2参22 相似文献
649.
650.
中国农业领域温室气体主要减排措施研究分析 总被引:1,自引:0,他引:1
气候变暖已成不争事实,主要是由于人为温室气体(GHG)排放增加所致,为减缓气候变暖趋势,各领域迫切需要采取减排措施;农业是一个重要的GHG排放源,农业领域采取减排措施对于减少我国GHG排放、保护农村生态环境有重要意义。文章在大量阅读前人研究结果的基础上,总结我国农业领域主要的减排管理措施,主要从农业活动、农村生活和生物质能源利用三方面进行阐述,并简要分析各措施的减排效果和存在问题。分析发现,农业活动的水肥管理是农田温室气体减排的研究热点,但由于地域和管理流程上的差异,对措施的减排效果尚存在争议;农村生活中存在巨大的减排潜力,采取恰当的减排措施不但可以减少GHG排放,还可以改善农村生态状况和环境卫生条件;农村生物质能源有很大发展潜力,合理开发利用,可以有效替代化石能源消耗,缓解能源危机,减少GHG排放,保护生态环境。总之,在农业领域采取积极的减排措施,有助于国家效应对气候变化,降低农业源污染和GHG排放,减轻环境压力,转换农业发展模式,加速农业现代化,促进农业生产的可持续发展和社会主义新农村建设。 相似文献