全文获取类型
收费全文 | 588篇 |
免费 | 81篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 7篇 |
综合类 | 23篇 |
化学工业 | 179篇 |
金属工艺 | 1篇 |
机械仪表 | 5篇 |
建筑科学 | 60篇 |
矿业工程 | 10篇 |
能源动力 | 276篇 |
轻工业 | 33篇 |
水利工程 | 5篇 |
石油天然气 | 62篇 |
无线电 | 4篇 |
一般工业技术 | 14篇 |
冶金工业 | 1篇 |
原子能技术 | 1篇 |
自动化技术 | 6篇 |
出版年
2023年 | 5篇 |
2022年 | 16篇 |
2021年 | 18篇 |
2020年 | 33篇 |
2019年 | 28篇 |
2018年 | 29篇 |
2017年 | 22篇 |
2016年 | 40篇 |
2015年 | 26篇 |
2014年 | 48篇 |
2013年 | 48篇 |
2012年 | 41篇 |
2011年 | 70篇 |
2010年 | 39篇 |
2009年 | 35篇 |
2008年 | 31篇 |
2007年 | 25篇 |
2006年 | 30篇 |
2005年 | 16篇 |
2004年 | 16篇 |
2003年 | 12篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有687条查询结果,搜索用时 15 毫秒
111.
112.
V. Fernández‐Cegrí F. Raposo M.A. de la Rubia R. Borja 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2013,88(5):924-929
BACKGROUND: The effects of chemical and thermochemical pretreatments on the composition and anaerobic biodegradability of sunflower oil cake were studied to compare these pretreatments and to assess their effectiveness. Four reagents (lime, sodium hydroxide, sulphuric acid, and sodium bicarbonate) at concentrations of 25% (w/w) of dry weight of substrate and 20 g L?1 substrate concentration were used for the chemical pretreatment for 4 h. The same conditions were used for thermochemical pretreatment with heating at 75°C. After the pretreatments, the solid and liquid fractions were separated and subjected to biochemical methane potential tests. RESULTS: The methane yields of the solid fraction obtained with lime, sodium hydroxide, sulphuric acid and bicarbonate were 130±9, 54±4, 61±6 and 88±7 mL CH4 g‐1CODadded, respectively, and after thermochemical pretreatment were 26±2, 84±7, 74±7, and 77±6 mL CH4 g‐1CODadded, respectively. The methane yields for liquids were 152±13, 2±0, 0±0, 249±19 mL CH4 g‐1CODadded, for the chemical pre‐treatment, respectively, and after the thermochemical pretreatment were 273±13, 58±5, 0±0 and 145±12 mL CH4 g‐1CODadded, respectively. CONCLUSION: Only the solid fraction obtained after the chemical pretreatment with lime gave a methane yield higher (130 mL CH4 g‐1CODadded) than the obtained for the untreated solid material (114 mL CH4 g‐1CODadd). No thermochemical pretreatment enhanced the methane yield of the solid or liquid fractions of the untreated material. © 2012 Society of Chemical Industry 相似文献
113.
Gülseren Pekin Senem Haskök Sayit Sargın Yüksel Gezgin Rengin Eltem Erdinç İkizoǧlu Nuri Azbar Fazilet Vardar Sukan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(7):976-982
BACKGROUND: Olive oil production is an important economical activity in the Aegean region of Turkey. However, the effluents of the olive oil producing mills with their high organic loads and toxic compounds are causing serious environmental problems. The anaerobic biological treatment of olive mill wastewater (OMWW) using the treatment plants of the regional industries could be a method of choice and within the scope of this study floccular and granular sludges were investigated in batch mode for their success in the treatment of OMWW while producing biogas. The major limitation of this treatment is the inhibition of methanogenic bacteria by the phenolic compounds in OMWW. Thus an integrated solution was suggested in which a pre‐treatment step (dephenolization) was also introduced before biological step. RESULTS: The effluents of 27 olive mills out of 47 were found to have total phenolics (TP) less than 3 g L?1 and could be treated anaerobically after simple dilution. The biogas production for the untreated OMWW was higher for floccular sludge than for the granular sludge (68.5 mL and 45.7 mL respectively). Combined pre‐treatment experiments, first coagulation with polyaluminum chloride, followed by flocculation with cationic polyelectrolyte and finally Fenton's oxidation, could remove 80% of TP and 95% of the total suspended solids. CONCLUSION: OMWW having TP values less than 3 g L?1 can be treated anaerobically using floccular sludge after simple dilution and biogas can be produced. For OMWW samples having higher TP values pre‐treatment is necessary and the pre‐treatment given in this study may be used effectively. Copyright © 2010 Society of Chemical Industry 相似文献
114.
沼气发酵猪粪管理系统对温室气体排放的影响 总被引:1,自引:0,他引:1
基于生命周期清单分析以及清洁发展机制,引入"碳足迹"概念,对我国散养猪以及规模化养猪场引入沼气发酵系统后猪粪管理系统温室气体排放及减排进行了估算。农户散养猪粪处理系统中,12 m3沼气池厌氧发酵过程碳足迹为223.40 kg CO2e/a,沼气代替原煤燃烧减少444.33 kg CO2e/a温室气体,沼气发酵净减少220.93 kg CO2e/a温室气体,我国散养生猪产生的猪粪以此沼气池发酵可减少温室气体20 984.62 Gg CO2e/a;分析运行规模约1 000 m3大型沼气工程的碳足迹,保守估计为2 835.32 t CO2e/a,运行沼气工程替代煤炭以及减少猪粪排放的温室气体共约2 914.23 t CO2e/a,故沼气工程年减少温室气体78.91 t CO2e,该项目共可减排1 578.20 t CO2e。在猪粪管理系统中采用沼气发酵系统可以更好地促进温室气体减排的进行。 相似文献
115.
116.
117.
118.
119.
120.