全文获取类型
收费全文 | 3909篇 |
免费 | 58篇 |
国内免费 | 75篇 |
专业分类
电工技术 | 21篇 |
综合类 | 102篇 |
化学工业 | 1651篇 |
金属工艺 | 239篇 |
机械仪表 | 179篇 |
建筑科学 | 197篇 |
矿业工程 | 19篇 |
能源动力 | 112篇 |
轻工业 | 310篇 |
水利工程 | 6篇 |
石油天然气 | 19篇 |
武器工业 | 3篇 |
无线电 | 102篇 |
一般工业技术 | 890篇 |
冶金工业 | 84篇 |
原子能技术 | 36篇 |
自动化技术 | 72篇 |
出版年
2023年 | 46篇 |
2022年 | 77篇 |
2021年 | 78篇 |
2020年 | 76篇 |
2019年 | 75篇 |
2018年 | 88篇 |
2017年 | 102篇 |
2016年 | 112篇 |
2015年 | 150篇 |
2014年 | 170篇 |
2013年 | 343篇 |
2012年 | 186篇 |
2011年 | 279篇 |
2010年 | 197篇 |
2009年 | 206篇 |
2008年 | 185篇 |
2007年 | 177篇 |
2006年 | 156篇 |
2005年 | 144篇 |
2004年 | 134篇 |
2003年 | 136篇 |
2002年 | 121篇 |
2001年 | 93篇 |
2000年 | 74篇 |
1999年 | 90篇 |
1998年 | 93篇 |
1997年 | 77篇 |
1996年 | 68篇 |
1995年 | 60篇 |
1994年 | 49篇 |
1993年 | 48篇 |
1992年 | 35篇 |
1991年 | 21篇 |
1990年 | 21篇 |
1989年 | 16篇 |
1988年 | 12篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 11篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有4042条查询结果,搜索用时 46 毫秒
21.
22.
氟挥发对氟化物乳白玻璃瓶罐生产的影响陆德明,周俊梅,付希英(山东轻工业学院250100)(山东德州玻璃厂253019)TheInfluenceofFluorineVolatilizationonProductionofFluorideopalGlas... 相似文献
23.
Athanasia M. Goula Thodoris D. Karapantsios Konstantinos G. Adamopoulos 《Drying Technology》2007,25(4):591-598
A contact probe test was developed to characterize the surface stickiness of a tomato pulp droplet at various moisture contents and temperatures. To provide tomato pulp samples with different moisture contents, tomato powder produced by a laboratory spray dryer was wetted to seven different moisture levels. The instantaneous tensile force curve was recorded during the probe withdrawal from which the maximum tensile force and other useful information were obtained and cross-examined against images of bonding, debonding, and failure of the material. Generally, at higher moisture contents tomato pulp exhibited cohesive failure followed by semi-adhesive failure, but when moisture content decreased to a certain level, a peak tensile pressure was observed and the failure was adhesive. In addition, higher temperatures shifted the points of adhesive failure toward lower moisture content. 相似文献
24.
R.H. Ericksen 《Polymer》1985,26(5):733-746
Creep of Kevlar 29, Kevlar 49 and PRD 49-III fibres was investigated. The fibres exhibited transient creep and the strain-time relationship was represented by a logarithmic time law. The creep strain recovered with time when the load was removed. Upon reloading to the same creep stress the strain-time relationship was again logarithmic but the creep rate was reduced. Modulus measurements were made during the creep test and these showed that the modulus increased with time. This result indicated a crystallite rotation mechanism which could account for the experimentally observed creep strain. Creep in PRD 49-III fibres exhibited a small temperature dependence over the temperature range 20°C to 150°C. The apparent creep activation energy was consistent with the range of values reported for hydrogen bonding. This suggests one possible creep mechanism in which the combined action of stress and thermal activation causes rearrangement of intercrystalline bonds in the crystallite boundaries resulting in boundary creep. Boundary creep allows crystallite rotation which produces the macroscopic creep strain. Boundary creep is discussed in terms of the fibre morphology and a model of delayed elasticity. 相似文献
25.
Yaping KeLU 《材料科学技术学报》2002,18(6):492-496
In this paper,glass transition and thermal stability of the Zr-Al-Cu-Ni metallic glasses were investigated by using electrical resistance measurement(ERM),DSC and X-ray diffraction techniques.The experimental results show that the ERM is capable of detecting the glass transition of the amorphous alloys and can help to distinguish the crystallization products of the Zr-Al-Cu-Ni metallic glasses owing to the difference of the electrical resistivity between the precipitation phases. 相似文献
26.
D Ganguli 《Bulletin of Materials Science》1993,16(6):523-531
The various parameters related to sol-gel processing are discussed with special reference to those which usually attract less
attention but depending on the final product in mind, can play important roles. The versatility of the sol-gel technique in
materials preparation is demonstrated by discussing the various products developed at the author’s laboratory by using this
processing method. 相似文献
27.
In this research, the biosorption of phenol using the fibres of a Mediterranean seagrass Posidonia oceanica (L.) was studied. Batch experimental procedures were made to investigate the ability of this novel marine biomass to remove phenol from aqueous phase. The influences of pH and contact time at different initial concentrations were evaluated. The results showed that biosorption capacity was enhanced using solution pH equal to 5.2. The modelling results showed that pseudo‐second‐order and Redlich‐Peterson models were found to be the most suitable to satisfactory describe the kinetic and equilibrium adsorption data, respectively. 相似文献
28.
Asbestos fibres, of the chrysotile variety, and chopped carbon fibres were pretreated by an in-situ polycondensation technique eventually resulting in a polyamide coating on the fibre surface. Ionomer based composites containing either carbon or asbestos fibres in random in plane fibre orientation were prepared, and the influence of this coating process on the tensile properties was investigated. It was found that for the asbestos-filled composites the presence of the nylon 6,6 interlayer improves the tensile performance, especially at moderate polyamide depositions. This is not the case with the pretreated carbon-filled composites for which carbon fibres with higher polyamide contents are preferred. Combinations of the treated asbestos fibres with carbon and/or aramid fibres may be used to reduce the asbestos content in asbestos-only based engineering plastics. 相似文献
29.
本文基于弹塑性分叉理论研究单向纤维增强复合材料的压缩破坏模式和压缩强度对缺陷的敏感性问题。对于常见复合材料,所得结论是:无缺陷或者小缺陷情况的破坏模式为倾斜破坏带;大缺陷情况的破坏模式为水平破坏带;形成水平破坏带的压力值小于形成倾斜破坏带的压力。 相似文献
30.
用扫描电镜研究硅酸盐、硼酸盐和磷酸盐玻璃的表面 总被引:1,自引:0,他引:1
王树传 《大连轻工业学院学报》1994,13(4):38-41
本文采用扫描电镜及能谱仪分别研究了硅酸盐、硼酸盐和磷酸盐玻璃的风化、离子注入和离子交换,观察了表面形貌、离子交换的深度分布及离子注入对表面析晶的影响。 相似文献