全文获取类型
收费全文 | 544篇 |
免费 | 41篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 75篇 |
金属工艺 | 2篇 |
机械仪表 | 15篇 |
建筑科学 | 34篇 |
能源动力 | 12篇 |
轻工业 | 104篇 |
水利工程 | 11篇 |
石油天然气 | 1篇 |
无线电 | 78篇 |
一般工业技术 | 92篇 |
冶金工业 | 97篇 |
自动化技术 | 59篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 16篇 |
2020年 | 12篇 |
2019年 | 18篇 |
2018年 | 15篇 |
2017年 | 14篇 |
2016年 | 20篇 |
2015年 | 16篇 |
2014年 | 19篇 |
2013年 | 27篇 |
2012年 | 33篇 |
2011年 | 45篇 |
2010年 | 25篇 |
2009年 | 37篇 |
2008年 | 27篇 |
2007年 | 20篇 |
2006年 | 19篇 |
2005年 | 15篇 |
2004年 | 16篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 12篇 |
1998年 | 30篇 |
1997年 | 18篇 |
1996年 | 14篇 |
1995年 | 5篇 |
1994年 | 10篇 |
1993年 | 11篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1972年 | 3篇 |
1969年 | 1篇 |
排序方式: 共有585条查询结果,搜索用时 15 毫秒
581.
Microbial fuel cells for sulfide removal 总被引:3,自引:0,他引:3
Rabaey K Van de Sompel K Maignien L Boon N Aelterman P Clauwaert P De Schamphelaire L Pham HT Vermeulen J Verhaege M Lens P Verstraete W 《Environmental science & technology》2006,40(17):5218-5224
Thus far, microbial fuel cells (MFCs) have been used to convert carbon-based substrates to electricity. However, sulfur compounds are ubiquitously present in organic waste and wastewater. In this study, a MFC with a hexacyanoferrate cathodic electrolyte was used to convert dissolved sulfide to elemental sulfur. Two types of MFCs were used, a square type closed to the air and a tubular type in which the cathode compartment was open to the air. The square-type MFCs demonstrated a potential-dependent conversion of sulfide to sulfur. In the tubular system, up to 514 mg sulfide L(-1) net anodic compartment (NAC) day(-1) (241 mg L(-1) day(-1) total anodic compartment, TAC) was removed. The sulfide oxidation in the anodic compartment resulted in electricity generation with power outputs up to 101 mW L(-1) NAC (47 W m(-3) TAC). Microbial fuel cells were coupled to an anaerobic upflow anaerobic sludge blanket reactor, providing total removals of up to 98% and 46% of the sulfide and acetate, respectively. The MFCs were capable of simultaneously removing sulfate via sulfide. This demonstrates that digester effluents can be polished by a MFC for both residual carbon and sulfur compounds. The recovery of electrons from sulfides implies a recovery of energy otherwise lost in the methane digester. 相似文献
582.
Fanie Rautenbach Mieke Faber Sunette Laurie Robert Laurie 《Journal of food science》2010,75(5):C400-C405
Abstract: The antioxidant contents (β-carotene, chlorogenic acid, and vitamin C) as well as the antioxidant capacity (ORAC, FRAP, and ABTS) of 4 sweetpotato varieties were measured in this study. The sweetpotato varieties were cultivated under different water regimes and also subjected to thermal processing. The results show that the 2 orange-fleshed varieties (Resisto and W-119) contain significant more β-carotene, chlorogenic acid, and vitamin C than the 2 cream-fleshed varieties (Bosbok and Ndou). Thermal processing decreased the carotenoid and vitamin C content of all the varieties but increased the chlorogenic acid content and antioxidant capacity. Drought stress appears to increase the β-carotene, vitamin C, and chlorogenic acid contents as well as the antioxidant capacity of some of the sweetpotato varieties, especially W-119. 相似文献
583.
Three alkyds of high hydroxyl numbers with oil lengths of 21, 30, and 41 were prepared from crude palm oil. The excess hydroxyl groups provided good compatibility with melamine resins, and also served as sites for crosslinking reactions. They were made into baking enamels by blending with 20% of a commercial melamine resin. All of them could be cured at temperatures below 200°C although thermodecomposition might occur above 290°C. The dry‐hard time of these enamels cured at temperatures between 140–180°C ranged from 10 to 180 min. Fourier transform infrared spectroscopy could be used to follow the major curing reactions. The absorbance of ? O? H and ? N? CH2? OCH3 groups showed significant reduction. The changes in the absorbance of these peaks with time and temperature were investigated. The predominant reaction was identified as the formation of methylene ether linkages. However, the self‐condensation reactions of the amino resin and ester linkages did not occur to any noticeable extent. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2309–2315, 2001 相似文献
584.
Several methods are available to remove hydrogen sulphide and volatile organic sulphides from ventilated air at sewage-treatment works. Some methods use alkaline and oxidative chemical scrubbers which may have high capital and operational costs. Other methods, such as bio-scrubbers and bio-filters, are used to biochemically oxidize sulphides. Biological scrubbers have the advantage of low operating costs, but their performance may be adversely affected by a high concentration of sulphide (> 100 ml/m3 ).
This paper describes the development of a novel, compact and low-cost 'rusty-iron' chemical filter which catalyzes the oxidation of hydrogen sulphide and organic sulphides to colloidal sulphur and water. Operating costs are relatively low, with no need for routine maintenance. Full-scale demonstration of the effectiveness of such filters was carried out over two years at several treatment works, the results of which are described and discussed together with details of capital costs. The overall percentage removal of hydrogen sulphide by compact multistage filters was found to exceed 95%, irrespective of inlet sulphide concentrations which varied from 34 to 500 ml/m3 (ppm). 相似文献
This paper describes the development of a novel, compact and low-cost 'rusty-iron' chemical filter which catalyzes the oxidation of hydrogen sulphide and organic sulphides to colloidal sulphur and water. Operating costs are relatively low, with no need for routine maintenance. Full-scale demonstration of the effectiveness of such filters was carried out over two years at several treatment works, the results of which are described and discussed together with details of capital costs. The overall percentage removal of hydrogen sulphide by compact multistage filters was found to exceed 95%, irrespective of inlet sulphide concentrations which varied from 34 to 500 ml/m
585.
Siv Boon Mundal Johanne Johnsen Rakner Gabriela Brettas Silva Lobke Marijn Gierman Marie Austdal Purusotam Basnet Mattijs Elschot Siril Skaret Bakke Jenny Ostrop Liv Cecilie Vestrheim Thomsen Eric Keith Moses Ganesh Acharya Line Bjrge Ann-Charlotte Iversen 《International journal of molecular sciences》2022,23(4)