全文获取类型
收费全文 | 674篇 |
免费 | 53篇 |
国内免费 | 35篇 |
专业分类
电工技术 | 1篇 |
综合类 | 43篇 |
化学工业 | 489篇 |
金属工艺 | 48篇 |
机械仪表 | 7篇 |
建筑科学 | 8篇 |
矿业工程 | 14篇 |
能源动力 | 3篇 |
轻工业 | 2篇 |
石油天然气 | 5篇 |
武器工业 | 6篇 |
无线电 | 8篇 |
一般工业技术 | 84篇 |
冶金工业 | 42篇 |
原子能技术 | 2篇 |
出版年
2024年 | 2篇 |
2023年 | 16篇 |
2022年 | 24篇 |
2021年 | 21篇 |
2020年 | 18篇 |
2019年 | 15篇 |
2018年 | 21篇 |
2017年 | 24篇 |
2016年 | 12篇 |
2015年 | 14篇 |
2014年 | 25篇 |
2013年 | 22篇 |
2012年 | 29篇 |
2011年 | 34篇 |
2010年 | 18篇 |
2009年 | 33篇 |
2008年 | 19篇 |
2007年 | 28篇 |
2006年 | 29篇 |
2005年 | 24篇 |
2004年 | 34篇 |
2003年 | 37篇 |
2002年 | 31篇 |
2001年 | 33篇 |
2000年 | 37篇 |
1999年 | 17篇 |
1998年 | 23篇 |
1997年 | 20篇 |
1996年 | 11篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 4篇 |
1992年 | 16篇 |
1991年 | 28篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1979年 | 1篇 |
排序方式: 共有762条查询结果,搜索用时 62 毫秒
1.
In this investigation, low-cement castables were prepared using 70% alumina grog aggregates obtained from crushed alumina brick waste. The aggregates were thermally treated at 1550 °C for 3 h. Four types of low-cement castables were prepared with various types of aggregates (alumina grog with or without thermal treatment) and fillers (with or without zircon addition), and they were evaluated in terms of their physical, thermal, and chemical properties. Microstructural analysis via scanning electron microscopy (SEM) was performed on the castables before and after slag attack. Compared to the other fabricated castables, the thermally treated alumina grog castables with zircon showed better physical properties, such as a higher bulk density, cold crushing strength, and modulus of rupture and a lower apparent porosity and water absorption. In addition, they had a higher positive linear thermal expansion, refractoriness under load, permanent linear change, and hot modulus of rupture. The results of the SEM with energy dispersive X-ray analysis of the prepared castables confirmed that the mullite and anorthite phases were predominant when zircon was not added and the zircon–mullite phase additionally appeared upon the incorporation of zircon. A quantitative elemental analysis via X-ray fluorescence spectroscopy was employed to determine the composition of the castables. X-ray diffraction analysis showed that the alumina grog castables had a high mullite and low anorthite content, and the thermally treated alumina grog had a high anorthite, low mullite, and high zircon content. The improvement in the mechanical and thermo-mechanical properties of the castables with thermally treated alumina grog and added zircon can be attributed to the formation of the zircon–mullite phase with a low mullite phase content. 相似文献
2.
3.
4.
5.
Poor-grade fireclay products contain substantial amount of glass. A glass of similar composition was synthesized, nucleated
and heat-treated for crystallization of mullite. The size and size-distribution of mullite crystals, the rate of change of
size and the aspect ratio of the crystals were investigated in relation to the nucleating agents and temperature. 相似文献
6.
Duane J. Lewis 《Journal of the American Ceramic Society》1991,74(10):2410-2413
Mixed-oxide systems are of interest in a variety of technical ceramic applications. The key in many systems is to achieve a high degree of homogeneity, approaching the molecular level. A technique for producing mixed oxides via direct oxidation of mixtures of organometallic compounds is discussed as a potential route. Preliminary work performed on producing mullite is discussed. 相似文献
7.
8.
H. S. Tripathi B. Mukherjee S. K. Das A. Ghosh G. Banerjee 《Bulletin of Materials Science》2003,26(2):217-220
Mullite was developed by reaction sintering of sillimanite beach sand and calcined alumina. Two varieties of sillimanite beach
sand viz. S and Z having different compositions were selected. Synthesis and properties of mullite were very much dependent
on the sillimanite beach sand composition. Presence of higher amount of impurities in the Z-variety of sillimanite sand favours
the densification by liquid phase formation. Presence of zircon in Z-variety increases the hardness and fracture toughness.
Alumina addition improves the mechanical/thermomechanical properties of the samples. Mullite retains the usual orthorhombic
habit of sillimanite. Rounded to sub rounded zirconia dispersed within the mullite matrix of the sample ZA is noticed. 相似文献
9.
CeO2 和MgO助烧剂对矾土基莫来石合成料烧结的影响 总被引:1,自引:0,他引:1
以高铝矾土碎矿(w(Al2O3)为75%~84%)和煤矸石(w(Al2O3)约45%)为原料,按矾土基莫来石合成料的设计成分要求(w(Al2O3)为68%~72%)进行配比,于1500~1700℃分别保温3h煅烧合成了矾土基莫来石,并分别研究了助烧剂CeO2和MgO单独加入,CeO2 MgO复合加入,复合加入时CeO2与MgO的比例以及复合加入量对矾土基莫来石合成料烧结性能的影响。结果表明:加入CeO2 MgO复合助烧剂比单独加入CeO2或MgO的促烧结效果要好,当CeO2 MgO外加量为0.75%,CeO2与MgO质量比为1/1时,可使试样的烧结温度降至1600℃(不加助烧剂的为1700℃),得到显气孔率0.9%,体积密度为2.84g·cm-3,荷重软化开始温度为1570℃的合成莫来石;显微结构分析表明,此合成料荷重软化温度较高的原因是发育良好的柱状莫来石构成了交错连锁的网络结构,同时TiO2大部分固溶在莫来石晶体中。 相似文献
10.
Wenlong Zheng Xiao Chen Chunyang Liu Shiping Ren Li Zhang 《International Journal of Applied Ceramic Technology》2021,18(4):1244-1254
Silica-based ceramic cores are extensively used in investment casting process, during which they must exhibit sufficient flexural strength and deformation resistance. In this study, micro-sized mullite was used as an additive to silica-based ceramic cores to optimize their high temperature properties. To investigate the effects of micro-sized mullite on cristobalite crystallization, mechanical and thermal properties of silica-based ceramic cores, ceramic cores with different amounts of micro-sized mullite were fabricated. The XRD results showed that additional micro-sized mullite diminished the crystallization of cristobalite at high temperatures, primarily caused by the mullite related compressive stresses on the surface regions of fused silica particles. Three-point bending tests and SEM results showed that micro-sized mullite had a more significant effect on the flexural strength of ceramic cores compared with conventional additives. Particularly, the fracture mechanism of silica-based ceramic cores had been changed from intergranular fracture into a mixed fracture consisting of both intergranular and transgranular fracture. The mechanical and thermal properties of ceramic cores were all reduced slightly as the mullite content exceed 4.6 wt%. Hence, to optimize the properties of silica-based ceramic cores, the micro-sized mullite content should not exceed 4.6 wt%. 相似文献