全文获取类型
收费全文 | 214篇 |
免费 | 8篇 |
专业分类
综合类 | 2篇 |
化学工业 | 40篇 |
金属工艺 | 15篇 |
机械仪表 | 2篇 |
建筑科学 | 15篇 |
能源动力 | 10篇 |
轻工业 | 9篇 |
水利工程 | 2篇 |
无线电 | 43篇 |
一般工业技术 | 38篇 |
冶金工业 | 23篇 |
自动化技术 | 23篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 6篇 |
2014年 | 14篇 |
2013年 | 16篇 |
2012年 | 10篇 |
2011年 | 16篇 |
2010年 | 11篇 |
2009年 | 12篇 |
2008年 | 10篇 |
2007年 | 12篇 |
2006年 | 3篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 7篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 14篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有222条查询结果,搜索用时 15 毫秒
41.
Vítor J.P. Vilar Tânia F.C.V. Silva Marcos A.N. Santos Amélia Fonseca Isabel Saraiva Rui A.R. Boaventura 《Solar Energy》2012,86(11):3301-3315
The main purpose of this work is to study the treatment of a leachate after preliminary aerated lagooning by a solar photo-Fenton process, using a photocatalytic reactor with compound parabolic collectors (CPCs). The influence of different process parameters in the reaction rate was evaluated, such as, the type of acid used in the acidification step (H2SO4, HCl, H2SO4 + HCl); type of iron salt (FeSO4, FeCl3) and respective iron concentration (60, 80, 100 and 140 mg Fe2+/L); temperature; and ratio of illuminated to total volume (25 L/35 L; 25 L/72 L). DOC abatement in the acidification procedure is independent of the type of acid used and temperature, and is related principally with the precipitation of humic acids. The use of HCl alone or in combination with H2SO4 leads to a substantially increase of the chloride ions, leading to the formation of less reactive chloride radicals when compared with sulfate radicals, decreasing the photo-Fenton reaction rate. The use of ferrous ions instead of ferric ions influenced positively the photo-Fenton reaction. Meteorological conditions favoring higher temperature of the leachate enhance the photo-Fenton reaction. Alternating dark and illumination intervals has shown a negligible effect on the illumination time needed to achieve the same mineralization, indicating that the Fenton process that takes place in dark zones is not efficient, even in the degradation of intermediate compounds resulting from the light-enhanced reaction. According to biodegradability tests, the optimum energy dose, necessary to obtain a biodegradable effluent, is 57.4 kJUV/L, consuming 120 mM of H2O2 and leading to a final DOC of 284 mg/L which corresponds to approximately 66% of mineralization. 相似文献
42.
Insight into the Functional and Structural Properties of 3‐Arylcoumarin as an Interesting Scaffold in Monoamine Oxidase B Inhibition 下载免费PDF全文
43.
In the present work single and multiple layer NiCrAlY coatings were produced by laser cladding on (100) single-crystalline substrates of SRR99 Ni-based superalloy. Detailed structural characterisation and texture analysis by optical microscopy, scanning electron microscopy, X-ray diffraction and Rutherford backscattering showed that the NiCrAlY coatings consisted essentially of γ phase with yttrium oxide (Y2O3) and a small proportion of yttrium–aluminum garnet (Al5Y3O12) precipitated in the interdendritic regions. The coatings presented a columnar dendritic structure grown by epitaxial solidification on the substrate and inherited the single-crystalline nature and the orientation of the substrate. The coating material also showed a mosaicity and a defect density similar to those of the substrate. It can be expected that the protective effect of these coatings against oxidation is greatly enhanced compared with polycrystalline coatings because high diffusivity paths, such as grain boundaries, are eliminated in single-crystalline coatings, thus reducing mass transport through the coating. 相似文献
44.
Characterization of hydroxyl-terminated polybutadiene 总被引:1,自引:0,他引:1
Commercial samples of hydroxyl terminated polybutadienes (HTPB) were analysed by 1H and 13C NMR spectroscopy, in regard to hydroxylated end groups. The results were discussed and compared with those reported so far. 相似文献
45.
The present work shows that laser surface alloying of the creviced area on Al 7175-T7351 with chromium can avoid crevice corrosion. Corrosion takes places outside the crevice in conditions where the ratio of anodic area to cathodic area is favourable to minimize corrosion. As laser surface processing is adequate for treating small areas there is an enormous potential in this technology. 相似文献
46.
There is a distribution limit of sessile oak (Quercus petraea) in the northern half of the Iberian Peninsula, with its southernmost populations located at the xeric limit for the species. We present here the current distribution of these populations in the Montseny Massif (N.E. Catalonia) and how the surface area they cover has developed over the last 50 years. Using a new high-resolution map (1:5000) we have calculated that Q. petraea currently covers 64.1 ha, and is found between 450 and 1150 m above sea level with a predominantly southern exposure, with the north-facing slopes being dominated by beech forests. With regard to its recent development, 44% of what is now dense forest was, in 1956, much more dispersed while 11% of it consisted of open spaces or shrubs. Such changes clearly show that, in Montseny, Q. petraea is well capable of regenerating its forest canopy as well as colonising adjacent environments. 相似文献
47.
Tânia F.C.V. Silva M. Elisabete F. Silva A. Cristina Cunha-Queda Amélia Fonseca Isabel Saraiva M.A. Sousa C. Gonçalves M.F. Alpendurada Rui A.R. Boaventura Vítor J.P. Vilar 《Water research》2013
A multistage treatment system, at a scale close to the industrial, was designed for the treatment of a mature raw landfill leachate, including: a) an activated sludge biological oxidation (ASBO), under aerobic and anoxic conditions; b) a solar photo-Fenton process, enhancing the bio-treated leachate biodegradability, with and without sludge removal after acidification; and c) a final polishing step, with further ASBO. 相似文献
48.
49.
In this study an industrial algal waste from agar extraction has been used as an inexpensive and effective biosorbent for cadmium (II) removal from aqueous solutions. This biosorbent was compared with the algae Gelidium itself, which is the raw material for agar extraction. Equilibrium data follow both Langmuir and Redlich-Peterson models. The parameters of Langmuir equilibrium model are q(max)=18.0 mgg(-1), b=0.19 mgl(-1) and q(max)=9.7 mgg(-1), b=0.16 mgl(-1), respectively for Gelidium and the algal waste. Kinetic experiments were conducted at initial Cd(II) concentrations in the range 6-91 mgl(-1). Data were fitted to pseudo-first- and second-order Lagergren models. For an initial Cd(II) concentration of 91 mgl(-1) the parameters of the pseudo-first-order Lagergren model are k(1,ads)=0.17 and 0.87 min(-1); q(eq)=16.3 and 8.7 mgg(-1), respectively, for Gelidium and algal waste. Kinetic constants vary with the initial metal concentration. The adsorptive behaviour of biosorbent particles was modelled using a batch reactor mass transfer kinetic model. The model successfully predicts Cd(II) concentration profiles and provides significant insights on the biosorbents performance. The homogeneous diffusivity, D(h), is in the range 0.5-2.2 x10(-8) and 2.1-10.4 x10(-8)cm(2)s(-1), respectively, for Gelidium and algal waste. 相似文献
50.
Van Caenegem R. Colle D. Pickavet M. Demeester P. Christodoulopoulos K. Vlachos K. Varvarigos E. Stampoulidis L. Roccato D. Vilar R. 《Communications Magazine, IEEE》2007,45(11):52-61
Recent advances in the all-optical signal processing domain report high-speed and nontrivial functionality directly implemented in the optical layer. These developments mean that the all- optical processing of packet headers has a future. In this article we address various important control plane issues that must be resolved when designing networks based on all-optical packet-switched nodes. 相似文献