全文获取类型
收费全文 | 490篇 |
免费 | 66篇 |
国内免费 | 20篇 |
专业分类
电工技术 | 1篇 |
综合类 | 15篇 |
化学工业 | 214篇 |
机械仪表 | 6篇 |
建筑科学 | 13篇 |
矿业工程 | 3篇 |
能源动力 | 70篇 |
轻工业 | 206篇 |
水利工程 | 2篇 |
石油天然气 | 4篇 |
一般工业技术 | 38篇 |
冶金工业 | 4篇 |
出版年
2024年 | 4篇 |
2023年 | 7篇 |
2022年 | 14篇 |
2021年 | 15篇 |
2020年 | 17篇 |
2019年 | 23篇 |
2018年 | 18篇 |
2017年 | 15篇 |
2016年 | 28篇 |
2015年 | 12篇 |
2014年 | 30篇 |
2013年 | 38篇 |
2012年 | 57篇 |
2011年 | 51篇 |
2010年 | 30篇 |
2009年 | 21篇 |
2008年 | 14篇 |
2007年 | 21篇 |
2006年 | 21篇 |
2005年 | 18篇 |
2004年 | 13篇 |
2003年 | 12篇 |
2002年 | 10篇 |
2001年 | 17篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 12篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有576条查询结果,搜索用时 11 毫秒
61.
Solange I Mussatto Júlio C Santos Walter C Ricardo Filho Silvio S Silva 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2006,81(11):1840-1845
Xylitol was recovered from fermented sugarcane bagasse hemicellulosic hydrolysate by adsorption and crystallization procedures. Silica gel adsorption was employed to purify the broth containing xylitol. In this step, different mixtures of the solvents ethyl acetate, ethanol and acetone were used as eluent, and different proportions of fermented broth volume incorporated per gram of silica gel (Vb/Msg, varying from 1.0 to 2.0 cm3 g?1) were used to pack the column employed as stationary phase bed. The xylitol purification efficiency varied for each mixture of solvent, and for each Vb/Msg ratio used. The purified broth was submitted to different crystallization procedures (cooling, concentration and supplementation with commercial xylitol) aiming to recover xylitol crystals. The best result (60% crystallization yield and 33% total recovery of xylitol from fermented broth) was obtained when the column was packed with a Vb/Msg ratio of 2 cm3 g?1, and the broth was purified with a mixture of ethyl acetate and ethanol, concentrated 6.5‐fold, and supplemented with commercial xylitol to force the precipitation. Copyright © 2006 Society of Chemical Industry 相似文献
62.
63.
64.
Ke Qi Lau Mohd Redzwan Sabran Siti Raihanah Shafie Sook Wah Chan 《International Journal of Food Science & Technology》2022,57(7):4586-4593
Sugarcane bagasse (SB) is one of the most abundant food wastes. In this research, SB was incorporated into the development of noodles at three different ratios, i.e. 5%, 10% and 15%. Total dietary fibre of noodles significantly increased from 3.39% (control noodles; – without SB) to 13.85% with 15% SB incorporation. All SB incorporated noodles (SBNs) were qualified to be labelled as ‘High in dietary fibre’. The 15% SBN had the highest fibre content and lowest dialyzable glucose, but the organoleptic properties were the lowest. Due to that, 5% SBN was deemed to be the most suitable ratio for noodles incorporation, as it had the closest value towards the commercial noodles in terms of colour, texture, fibre content and dialyzable glucose concentration of noodles samples. In terms of sensory evaluation, the 5% SBN had the highest overall acceptability, and the ratio was suitable for noodles development. 相似文献
65.
在硫酸的催化作用下,甘蔗渣在聚乙二醇和甘油的混合溶剂中能被液化成生物质多元醇。向液化试剂中加入表面活性剂,利用表面活性剂提高液化试剂对甘蔗渣的渗透能力,改善甘蔗渣的液化效果。主要研究了表面活性剂种类和浓度、液化时间、液固比,液化试剂组成、催化剂浓度等对液化效果的影响。结果表明,吐温-80对甘蔗渣液化的效果最明显,并且在用量为0.25%时,液化效果最好,转化率达99%以上。液化得到的生物质多元醇的羟值为500—700mgKOH/g。红外光谱分析表明,液化产物中含有大量的可反应羟基,可以作为制备聚氨酯硬泡的多元醇组分。 相似文献
66.
The impact of maturation on concentrations of key odour active compounds which determine the aroma of tequila 下载免费PDF全文
Ivonne Wendolyne González‐Robles David J. Cook 《Journal of the Institute of Brewing》2016,122(3):369-380
Samples of non‐mature and añejo (matured) tequila of the same brand/provenance were analysed using GC–MS and gas chromatography olfactometry (GC‐O)/aroma extract dilution analysis (AEDA) to provide quantitative data on the most odour active compounds that contribute to the aroma of these spirits. Extracts of non‐mature tequila were characterized by 26 odour‐active regions, which included ethyl hexanoate, ethyl octanoate, 2‐phenylethyl acetate, β‐damascenone, isoamyl alcohol and octanoic acid as the most odour‐active compounds (flavour dilution, FD, factor ≥ 6561). In contrast, extracts of the mature spirit showed 36 odour‐active zones, where the compounds with the highest FD factors (6561) were ethyl hexanoate, ethyl octanoate, 2‐phenylethyl acetate, isoamyl alcohol, phenethyl alcohol, guaiacol, 4‐ethyl guaiacol, vanillin, cis/trans whisky lactones, β‐damascenone and octanoic acid. The aromagram of mature tequila was thus differentiated from that of the non‐mature spirit owing to the presence of cask‐extractive compounds and the increased FD factors of certain terpenes, higher alcohols and acetals. This study provides a comprehensive and quantitative understanding of changes in key odourants of tequila as a result of the maturation process and also reveals a further characterization of the likely impact of each compound on overall spirit flavour, in terms of odour activity values. Copyright © 2016 The Institute of Brewing & Distilling 相似文献
67.
Many of the large-scale biomass combustion systems for producing heat, hot water, or steam accept biomass fuels containing relatively large amounts of moisture. Dry biomass burns at higher temperatures and thermal efficiencies than wet biomass. Flame temperature is directly related to the amount of heat necessary to evaporate the moisture contained in the biomass, the lower the moisture content, the lower the amount of energy needed to remove the water and the higher the boiler efficiency. In this article, a simple predictive tool is developed to estimate boiler efficiency as a function of stack gas temperature and sugarcane bagasse moisture content. The method quantitatively illustrates the effect of moisture content on the performance of a thermochemical process, for the direct combustion of sugarcane bagasse in a conventional boiler. The results are found to be in excellent agreement with reported data in the literature with average absolute deviation being around 1%. The tool developed in this study can be of immense practical value for engineers to have a quick check on biomass moisture content on the boiler performance at various conditions without opting for any experimental trials. In particular, engineers would find the approach to be user-friendly with transparent calculations involving no complex expressions. 相似文献
68.
The objective of this study was to optimize the culture conditions for simultaneous saccharification and fermentation (SSF) of cellulose for bio-hydrogen production by anaerobic mixed cultures in elephant dung under thermophilic temperature. Carboxymethyl cellulose (CMC) was used as the model substrate. The investigated parameters included initial pH, temperature and substrate concentration. The experimental results showed that maximum hydrogen yield (HY) and hydrogen production rate (HPR) of 7.22 ± 0.62 mmol H2/g CMCadded and 73.4 ± 3.8 mL H2/L h, respectively, were achieved at an initial pH of 7.0, temperature of 55 °C and CMC concentration of 0.25 g/L. The optimum conditions were then used to produce hydrogen from the cellulose fraction of sugarcane bagasse (SCB) at a concentration of 0.40 g/L (equivalent to 0.25 g/L cellulose) in which an HY of 7.10 ± 3.22 mmol H2/g celluloseadded. The pre-dominant hydrogen producers analyzed by polymerase chain reaction-denaturing gel gradient electrophoresis (PCR-DGGE) were Thermoanaerobacterium thermosaccharolyticum and Clostridium sp. The lower HY obtained when the cellulose fraction of SCB was used as the substrate might be due to the presence of lignin in the SCB as well as the presence of Lactobacillus parabuchneri and Lactobacillus rhamnosus in the hydrogen fermentation broth. 相似文献
69.
70.
蔗渣氧碱制浆工艺探讨 总被引:3,自引:0,他引:3
对蔗渣的氧碱制浆进行了初步研究。结果表明,用碱量、氧压是左右制浆效果的主要因素。蔗渣氧碱制浆的最佳工艺条件:用碱量25%,蒸煮最高温度140℃,氧压0.8MPa,转速400r·min-1,保温40min或零保温,液比1∶8,保护剂MgSO4添加量2.0%。在此条件下,制浆的综合质量指标最好。 相似文献