全文获取类型
收费全文 | 160篇 |
免费 | 9篇 |
国内免费 | 12篇 |
专业分类
安全科学 | 40篇 |
废物处理 | 5篇 |
环保管理 | 22篇 |
综合类 | 87篇 |
基础理论 | 5篇 |
污染及防治 | 11篇 |
评价与监测 | 4篇 |
社会与环境 | 6篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 1篇 |
2020年 | 7篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 11篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 6篇 |
2012年 | 10篇 |
2011年 | 19篇 |
2010年 | 8篇 |
2009年 | 10篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 10篇 |
2005年 | 12篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1987年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有181条查询结果,搜索用时 15 毫秒
101.
地源热泵对武汉节能减排的影响分析 总被引:1,自引:0,他引:1
地源热泵是利用浅表地热能实现空气温度调节的新技术,具有节能、环保的明显效应。武汉独特的地理气候条件和丰富的地下水资源使得地源热泵系统具有广阔的发展空间,示范工程的成功运行为大规模推广地源热泵技术提供了可靠依据。在武汉建设"两型社会"进程中,应采取总体规划、集中管理、专项扶持和鼓励创新等措施,以充分发挥地源热泵技术对武汉"节能减排"的重要作用。 相似文献
102.
天津地区蕴藏着丰富的低温地热资源,分析表明,开发地热能并使用水源热泵对室内进行供暖是可行的,与燃煤热水锅炉供热相比,具有节省矿物能源、降低成本、保护环境的优势,适合在天津及广大北方地区推广。 相似文献
103.
An untreated sewage source heat pump system directly makes use of the urban raw sewage instead of that treated by a sewage plant. At present In China, most systems adopt the indirect mode for avoiding the harmful effect of the sewage on the heat pump unit. In this article a direct-mode untreated sewage source heat pump system, which shows less theoretical analysis of the mathematical model, is theoretically designed and analyzed to simulate the system dynamic characteristics in the heating mode. The results show that the system COP changes from 4.1 to 3.4 and the heating capacity from 9.5 to 15.3 kW when the sewage inlet temperature is 12°C and the frequency increases from 18 to 32 HZ. The condenser heat-transfer coefficient increases with the frequency reducing while the change trend of evaporator heat-transfer coefficient is the opposite. The highest values of them are 303 and 1617 W.m?2?K?1, respectively. The frequency control simulation supplies the operation adjustment with theoretical instructions and some reference values. 相似文献
104.
Gajendra Singh Biplab Bhattacharya G.N. Tiwari 《International Journal of Sustainable Engineering》2016,9(3):170-181
A modified brushed permanent magnet DC (PMDC) motor has been developed and fabricated for a photovoltaic (PV)-operated solar systems. The conventional PMDC motor has been plagued with constraints, the most critical being ingestion of vapours of working fluid inside the rotor and stator, damaging the insulation of windings and forming a thin film of moisture between commutator and brushes. This flaw results into a very low mean time between failures of the motor. In the past, many attempts have been made where-in variety of seals to isolate the working fluid vapours from inner parts of motor have been tried out, but to no avail. Even Brushless DC motors have been designed in the past but their exorbitant cost makes the entire arrangement not viable economically. The modification attempted in this article overcomes the problem of working fluid ingestion inside the motor. It is found that mass flow rate of working fluid obtained at maximum peak sunshine hours is 17.5 l/min at 3030 rpm of motor driven by a PV module of 40 W at 16.20 V. This low-cost modified PMDC motor has been robust with high mean time between failures as no breakdown observed during 18 months of operation. 相似文献
105.
A new variable-speed ground-coupled liquid desiccant air-conditioner was proposed and applied to a multi-storey office building in a temperate city of Kunming in China. Dynamic system simulations were performed to compare its performance with a constant-speed ground-source heat pump system. It was found that the use of the new system for a single-floor office reduced the annual unbalanced load to the ground heat exchanger borefield by nearly 70% together with a borehole depth reduction of up to 30%. For the case of a multi-storey office building, the number of floors served could be increased by 144% together with a reduction of CO2 emission by 43%. The results highlighted the merit of the new hybrid system with enhanced applicability when it was applied to a multi-storey office building in a temperate city. 相似文献
106.
107.
典型高混接率分流制排水泵站雨天放江污染特征研究 总被引:1,自引:0,他引:1
通过对上海市中心城区典型分流制系统z泵站汛期降雨放江水质水量分析,在调查系统服务区特点、泵站运行和开展现场实测的基础上,得出如下结论:(1)由于管网系统混接情况严重,加上高水位运行、雨前预抽空等原因,Z泵站汛期放江频率高,污染严重;(2)放江污染物的EMC在不同雨型情况下表现不同,溶解性污染物随降雨量的增大而降低,而包含悬浮物的污染指标呈先升后降的变化趋势,这主要与管道沉积物特征有关;(3)随着降雨量的增大,泵站的放江负荷量显著增加。在同等降雨条件下,前峰雨使得泵站放江污染负荷远大于后峰雨;(4)受雨型与预抽空的影响,不论小雨、中雨、大雨,SS初期效应均不显著;COD与TP主要来源于管道沉积污染物,初期效应显著;溶解态污染物初期效应显著,不受降雨雨量与雨型的影响;(5)为有效降低Z泵站降雨放江污染负荷,提出包括雨污混接改造、优化泵站运行、提高截流能力、疏通管道等措施在内的污染控制策略。 相似文献
108.
109.
高压开关柜长期连续运行在高温高湿环境下,内部的阻燃绝缘件会老化而导致性能劣化,进而引起电弧击穿乃至着火事故。为揭示绝缘件样品老化对其击穿与引燃特性的影响机制,针对已在役运行12年开关柜内老化阻燃固封极柱样品和同配方新样品,开展了微观形貌、热重-差示扫描量热、热重-红外光谱和微量燃烧特性综合分析。结果表明:开关柜内的长期电热应力易使环氧树脂绝缘材料的微观结构产生破坏,内部易产生孔洞和裂纹,导致其绝缘性能下降;开关柜内的高温环境易使绝缘材料内部分子链缓慢断裂,导致老化样品更易受热分解;同时,柜内高温高湿环境既可使其材料内部孔隙吸湿而降低绝缘性能,还易导致磷系阻燃剂吸潮氧化,降低其阻燃性能;最后,与新样品相比,12年老化样品在升温初期的燃烧释热更高,一旦形成击穿电弧,更易着火燃烧。研究结果为高压开关柜因绝缘件老化失效而形成击穿起火事故提供了分析要点,并可作为未来更高性能阻燃绝缘件的优化设计依据。 相似文献
110.
通过对油田集油站泵房噪声污染现状及来源分析,提出噪声治理方案。经过噪声治理,集油站电机噪声平均降低至84dB(A),值班室噪声降低至58dB(A),达到GBJ 87-85《工业企业噪声控制设计规范》中的要求,治理后的降噪效果明显。 相似文献