全文获取类型
收费全文 | 2532篇 |
免费 | 234篇 |
国内免费 | 585篇 |
专业分类
安全科学 | 374篇 |
废物处理 | 203篇 |
环保管理 | 456篇 |
综合类 | 1520篇 |
基础理论 | 301篇 |
环境理论 | 4篇 |
污染及防治 | 299篇 |
评价与监测 | 84篇 |
社会与环境 | 75篇 |
灾害及防治 | 35篇 |
出版年
2024年 | 11篇 |
2023年 | 50篇 |
2022年 | 59篇 |
2021年 | 86篇 |
2020年 | 113篇 |
2019年 | 99篇 |
2018年 | 64篇 |
2017年 | 95篇 |
2016年 | 128篇 |
2015年 | 107篇 |
2014年 | 142篇 |
2013年 | 221篇 |
2012年 | 225篇 |
2011年 | 226篇 |
2010年 | 151篇 |
2009年 | 174篇 |
2008年 | 120篇 |
2007年 | 152篇 |
2006年 | 145篇 |
2005年 | 130篇 |
2004年 | 120篇 |
2003年 | 123篇 |
2002年 | 117篇 |
2001年 | 81篇 |
2000年 | 84篇 |
1999年 | 71篇 |
1998年 | 61篇 |
1997年 | 65篇 |
1996年 | 39篇 |
1995年 | 39篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有3351条查询结果,搜索用时 15 毫秒
991.
将新型智能化曝气控制系统(automatic oxygen supply device,AOSD)应用于A/O工艺中,对比分析AOSD系统曝气模式控制下的A/O工艺(I-A/O)与常规曝气模式A/O工艺(C-A/O)对活性污泥驯化作用、微生物菌群的分布影响,深入探讨I-A/O活性污泥特性演化对内源反硝化脱氮的作用机制.结果表明I-A/O系统出水NH4+-N、NO2--N出现一定积累效应,活性污泥在驯化过程中表现为更为显著的微膨胀,在外源碳素充盈状况下能更充分地将污泥混合液中的溶解性COD(SCOD)富集,将其转化为糖原(Gly),并在外源碳素供应匮乏的状况下激发内源反硝化脱氮反应,内源反硝化速率(EDNR)平均可达0.83 mg·(L·h)-1,超过C-A/O水平.通过Illumina HiSeq高通量测序技术对两系统污泥微生物群落结构解析:两系统污泥微生物群落多样性评估区别不明显,而I-A/O污泥中Candidate division TM7大量增殖是构成其丝状菌污泥微膨胀、Gly贮存能力提高的优势功能菌.AOSD的供氧模式使活性污泥特性与微生物群落在适应新环境上发生了特异性变化,好氧异养菌代谢活性下降,内源反硝化脱氮途径的强化使I-A/O实现了一种总体低氧需求的动态平衡状态. 相似文献
992.
薛朝妹 《中国安全生产科学技术》2011,7(8):203-206
油库是储存易燃易爆油品的专用场所,雷电是油库安全生产的重大隐患,油库防雷已成为关系到经济建设、社会发展和人民生命财产安全的重大课题。针对目前我国油库雷击事故频繁发生的问题,在对大量事故资料研究的基础上,分析了油库雷击火灾爆炸事故的原因,指出雷电产生的火花引燃油气是导致油库火灾爆炸的主要原因。并重点从安全管理学的角度,运用事故预防与控制的"3E"对策,分别从安全技术、安全管理、安全教育三个方面探讨了油库雷击事故的预防与控制措施。 相似文献
993.
Mendoza-Cantú A Heydrich SC Cervantes IS Orozco OO 《Journal of environmental management》2011,92(7):1706-1713
The oil industry is one of the main productive activities in Mexico and has a huge infrastructure, including a wide pipeline network that crosses urban, industrial, agricultural and natural areas. The threat of crude oil spills is greatest in those regions with a high concentration of oil extraction and refining activities, as in the case of the Coatzacoalcos and Tonalá Rivers Low Basin. This study ranked the geosystems of the basin in terms of vulnerability to pipeline crude oil spills. Very high vulnerability (level I) was assigned to the water bodies (lakes and rivers) and their margins of influence, including surfaces that flood during normal hydraulic load. High vulnerability areas (level II) comprised surfaces that can flood during extraordinary hydraulic load related with extreme hydrometeorological events. The remaining three vulnerability levels were defined for areas with low or negligible flooding potential, these were ranked according to physical (slope, relief and permeability), biological (richness, singularity and integrity) and socio-economic (social marginalization index and economic activities index) conditions. These results are presented on a map for better visualization and interpretation. This study will be useful to establish preventive and effective emergency management actions in order to reduce remediation costs and adverse effects on wild species. It also can help local and national authorities, oil industry and civil protection corps to better protect ecosystems, natural resources and human activities and goods. 相似文献
994.
Due to ever increasing quantities of waste materials and industrial by-products, solid waste management is the prime concern in the world. Scarcity of land-filling space and because of its ever increasing cost, recycling and utilization of industrial by-products and waste materials has become an attractive proposition to disposal. There are several types of industrial by-products and waste materials. The utilization of such materials in concrete not only makes it economical, but also helps in reducing disposal concerns. One such industrial by-product is waste foundry sand (SFS). Waste foundry sand is a by-product of ferrous and nonferrous metal casting industries. Foundries successfully recycle and reuse the sand many times in a foundry. When the sand can no longer be reused in the foundry, it is removed from the foundry and is termed as waste foundry sand.Published literature has shown that WFS could be used in manufacturing Controlled Low-Strength Materials (CLSM) and concrete. This paper presents an overview of some of the research published on the use of WFS in concrete. Effect of WFS on concrete properties such as compressive strength, splitting tensile strength, modulus of elasticity, freezing-thawing resistance, and shrinkage are presented. 相似文献
995.
R.P. Singh A. EmbrandiriM.H. Ibrahim N. Esa 《Resources, Conservation and Recycling》2011,55(4):423-434
Solid waste management is one of the challenging problems worldwide and it is becoming more complex by the increase in population and subsequently the waste generated. In Malaysia, among industrial solid waste palm oil mill waste (POMW) contributes the highest share. Wastes from the oil palm mill includes palm oil mill effluent (POME), decanter cake, empty fruit bunches, seed shells and the fibre from mesocarp. Generally most of the waste generated is either disposed of via open dumping or used as fertilizers as such or as animal feed. Land application of POMW and POME is very common practice as it contains numbers of plant nutrients. Direct application of POMW into agricultural soil can result in a number of problems such as water pollution, leaching etc. To deal with these problems, vermicomposting of palm oil mill waste may be a sustainable waste management option.There are number of researches going on management of biomass residues from palm oil mill, but very few works are going on vermicomposting of these agro-industrial waste. Vermicomposting of POMW can be a good practice as it will also be helpful in recycling the useful plant nutrients and it is better than that of composting process. Present review deals with the various aspects of vermicomposting of POMW and its importance. Review also put forward the effect of potential application of vermicompost on plant growth. On the whole it looks for the possibility of vermicomposting of waste from palm oil mill as a sustainable waste management alternative. 相似文献
996.
997.
煤层干式钻进粉尘扩散规律的研究 总被引:2,自引:0,他引:2
针对煤层干式钻进过程中粉尘污染严重的问题,分别对新庄孜矿c13煤层及10煤层干式钻进粉尘的分散度和煤的硬度进行测定,分析对比2煤层钻进时粉尘在3 m/s风速下的浓度分布情况;并针对C13煤层,在1.5 m/s,2.3 m/s和3 m/s的风速下测定粉尘浓度分布情况.根据粉尘浓度的实测数据,分析煤层干式钻进粉尘扩散规律.... 相似文献
998.
粤东凤凰山茶区土壤氟化学形态特征及其影响因素 总被引:2,自引:0,他引:2
采用连续化学提取法对粤东凤凰山茶区12个较大型茶园共60份土壤样品氟的5种化学形态分布进行研究.结果发现,土壤中氟的5种化学形态分布的规律为残余态〉〉铁锰结合态〉有机态〉水溶态〉可交换态.水溶态氟含量与可交换态氟含量、残余态氟含量及总氟含量呈显著正相关性,而铁锰结合态含量与有机束缚态之间呈显著正相关性,残余态与总氟之间... 相似文献
999.
1000.
事故状态下储油库水体污染的预防与控制 总被引:1,自引:1,他引:0
文章结合实例分析了储油库在事故状态下次生水体污染事件的风险,通过典型事故案例剖析了储油库水污染预防与控制管理的关键环节,指出国内相关标准在储油库水污染预防与控制措施要求方面存在的不足,提出储油库水污染防控体系建设的构架以及管理措施建议。 相似文献