全文获取类型
收费全文 | 1288篇 |
免费 | 110篇 |
国内免费 | 301篇 |
专业分类
安全科学 | 278篇 |
废物处理 | 42篇 |
环保管理 | 189篇 |
综合类 | 750篇 |
基础理论 | 86篇 |
环境理论 | 3篇 |
污染及防治 | 104篇 |
评价与监测 | 83篇 |
社会与环境 | 164篇 |
出版年
2024年 | 12篇 |
2023年 | 80篇 |
2022年 | 57篇 |
2021年 | 90篇 |
2020年 | 70篇 |
2019年 | 53篇 |
2018年 | 56篇 |
2017年 | 66篇 |
2016年 | 91篇 |
2015年 | 121篇 |
2014年 | 78篇 |
2013年 | 124篇 |
2012年 | 85篇 |
2011年 | 125篇 |
2010年 | 38篇 |
2009年 | 46篇 |
2008年 | 42篇 |
2007年 | 59篇 |
2006年 | 41篇 |
2005年 | 34篇 |
2004年 | 29篇 |
2003年 | 31篇 |
2002年 | 31篇 |
2001年 | 45篇 |
2000年 | 45篇 |
1999年 | 34篇 |
1998年 | 41篇 |
1997年 | 23篇 |
1996年 | 14篇 |
1995年 | 19篇 |
1994年 | 3篇 |
1993年 | 8篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1699条查询结果,搜索用时 875 毫秒
461.
To further understand the dynamic mechanism of dust explosion through a vent duct, we designed a small-scale cylindrical vessel connected with a vent duct and performed a dust explosion venting experiment under different opening pressures using corn starch as the explosive medium in this study. The results show that weakening effect of duct on venting is positively correlated with the opening pressure. The explosion pressure in the duct presents a three-peak-structure with time, successively caused by the membrane breaking shock wave, the secondary explosion in the tube, and the continuous combustion, and decreases gradually with the propagation distance. Meanwhile, the three pressure peaks are positively correlated with the opening pressure, while the time interval between them goes to contrary. The increase of opening pressure leads to the increase of secondary explosion intensity and reverse flow in the vessel, further accelerates the reaction rate in the vessel, and then shortens the duration of combustion in the vessel until the phenomenon of flame reignition in the vessel disappears. 相似文献
462.
463.
464.
基于上海市能源与电力统计数据,参考政府间气候变化专门委员会(IPCC)及国内发电企业污染物排放相关研究报告,设定不同发电方式的装机比例,分析核算不同装机比例下SO2、NOX以及CO2的排放量与减排量。结果表明,装机比例提升10.0%,相比煤电装机,天然气装机的SO2、NOX及CO2的排放量分别降低90.2%、91.3%与99.9%,减排效果显著。新能源装机比例由5.0%提升至10.0%,SO2、NOX及CO2分别削减3.0×103、3.8×103、3.6×107 t。 相似文献
465.
The main emissions from coal combustion at thermal power plants are carbon dioxide (CO2), nitrogen oxides, sulfur oxides, chlorofluorocarbons (CFCs), and airborne inorganic particles such as fly ash and soot; CO2, methane, and CFCs are greenhouse gases. These emissions are considered to be partially responsible for harmful global climate change. This review summarizes the status of thermal power plants in India and their various types of emissions that directly or indirectly produce harmful effects on the environment and human health. Moreover, it focuses on various types of preventive measures used to avoid/minimize emissions. 相似文献
466.
In this study, methanol and organometallic MnO2 fuels were used to improve the properties of diesel fuel. In addition, the effect of methanol fuel on engine oil and a piston ring was also examined experimentally in a four-cylinder, direct injection diesel engine running at 200 bar. Three different diesel fuels were prepared by adding 5, 10 and 15% methanol to diesel fuel. In order to prevent phase separation, 1% dodecanol was added to the mixture. Organometallic compounds of manganese were synthesised to prepare the solutions. The most effective amount and performance of anti-freeze were determined. From the results, it was observed that carbon monoxide emissions decreased and NOx emissions increased with the increase in the amount of methanol. On the other hand, organometallic MnO2 increased the cetane number and decreased the freezing point, viscosity and flame temperature. 相似文献
467.
Kim KY Ko HJ Kim HT Kim YS Roh YM Lee CM Kim CN 《Environmental monitoring and assessment》2007,133(1-3):255-266
This on-site survey study was performed to determine the concentrations and emissions of aerial contaminants in the different
types of swine houses in Korea and then to present beneficial information available for Korean pig producers to manage optimal
air quality in swine house. The swine houses investigated in this research were selected based on three criteria; manure removal
system, ventilation mode and growth stage of swine. Mean concentrations of aerial pollutants in swine houses were 8 ppm for
ammonia, 300 ppb for hydrogen sulfide, 2 mg m−3 for total dust, 0.6 mg m−3 for respirable dust, 4 log(cfu m−3) for total airborne bacteria and 3 log(cfu m−3) for total airborne fungi, respectively. Mean emissions based on pig (liveweight; 75 kg) and area (m2) were 250 and 340 mg h−1 for ammonia, 40 and 50 mg h−1 for hydrogen sulfide, 40 and 50 mg h−1 for total dust, 10 and 15 mg h−1 for respirable dust, 1.0 and 1.3 log(cfu) h−1 for total airborne bacteria and 0.7 and 1.0 log(cfu) h−1 for total airborne fungi, respectively. In general concentrations and emissions of gases were relatively higher in the swine
houses managed with deep-pit manure system with slats and mechanical ventilation mode than the different swine housing types
whereas those of particulates and bioaerosol were highest in the naturally ventilated swine houses with deep-litter bed system. 相似文献
468.
室内尘埃中铅的赋存形态与儿童血铅的相关性研究 总被引:1,自引:1,他引:0
有关室内尘埃中铅的赋存形态与儿童血铅的相关性研究尚未见报道。在对某地儿童血铅进行调查期间,发现当地儿童血铅浓度与室内尘埃中铅的水溶态、离子交换态、腐殖酸结合态、铁锰氧化态、强有机结合态和残渣态呈正相关,但不显著,无统计学意义。但与总铅浓度呈显著正相关(R=0.447,P=0.032),与铅的碳酸盐结合态呈高显著相关(R=0.537,P=0.008)。在此基础上,将儿童血铅分别与尘埃中铅暴露量、摄入量和潜在剂量进行相关分析,结果表明,儿童血铅与室内尘总铅摄入量和总铅潜在剂量正相关但无统计意义,与尘总铅暴露量显著相关(R=0.431,P=0.040),与碳酸盐态的暴露量(R=0.537,P=0.008)、摄入量(R=0.538,P=0.008)和潜在剂量(R=0.540,P=0.008)高度显著相关。提示在土壤和尘埃中铅的碳酸盐态含量较高的地区,碳酸盐态铅可能是造成儿童血铅超标的主要原因。 相似文献
469.
北京市机动车尾气排放PM10组分特征研究 总被引:7,自引:4,他引:3
为提高机动车尾气排放可吸入颗粒物PM10成分谱的代表性和准确性,提出并采用在机动车尾气检测线上采用稀释通道采样器随机采集机动车排出PM10的采样方法。采集了591辆轻、重型汽油车和柴油车尾气排放PM10,测试并分析了颗粒物的27种组分。数据表明:机动车排放颗粒物PM10中含量丰富的组分为OC、EC、NH+4、NO-3和SO2-4;柴油车排放PM10中OC和EC的质量分数为49.08%,是汽油车(38.38%)的1.3倍,汽油车的OC/EC(2.36)是柴油车(0.78)的3倍;汽油车排放PM10中的二次转化产物(SO42-+NH4++NO3-)的质量分数为19.37%,是柴油车(3.57%)的5.4倍;汽油车排放NH+4是柴油车的5.3倍。 相似文献
470.
In this paper we introduce a new method of analysing the relationship between nitrogen dioxide (NO2) and oxides of nitrogen (NOx) concentrations using data from the UK National Air Quality Archive. The study includes analyses of measurements from two different types of site in London, a kerbside site: Cromwell Rd, and three background sites: Bridge Place, London Bloomsbury and West London, over several years (1991–7). The data in some years showed that hourly NO2 concentrations exceeded the UK Standard of 150 ppb. Data were binned, averaged, and polynomials fitted at each site. Analysis of the resulting polynomials was used to estimate reductions in NOx emission required to achieve the National Air Quality Strategy Objective. Examination of the empirical ratio NO2:NOx (the 'yield') gives an indication of the sensitivity of the NO2 to NOx controls and the amount of NO2 that would arise from modelled values of total oxides of nitrogen. The response of NO2 to emission changes is very non-linear, implying 30–45% controls on NOx may be required. 相似文献