全文获取类型
收费全文 | 33884篇 |
免费 | 2652篇 |
国内免费 | 1447篇 |
专业分类
电工技术 | 1499篇 |
综合类 | 3153篇 |
化学工业 | 2151篇 |
金属工艺 | 5307篇 |
机械仪表 | 5983篇 |
建筑科学 | 3089篇 |
矿业工程 | 1158篇 |
能源动力 | 541篇 |
轻工业 | 913篇 |
水利工程 | 696篇 |
石油天然气 | 880篇 |
武器工业 | 384篇 |
无线电 | 1018篇 |
一般工业技术 | 3879篇 |
冶金工业 | 5184篇 |
原子能技术 | 235篇 |
自动化技术 | 1913篇 |
出版年
2024年 | 128篇 |
2023年 | 377篇 |
2022年 | 724篇 |
2021年 | 937篇 |
2020年 | 1046篇 |
2019年 | 792篇 |
2018年 | 758篇 |
2017年 | 1093篇 |
2016年 | 1174篇 |
2015年 | 1260篇 |
2014年 | 1913篇 |
2013年 | 1843篇 |
2012年 | 2194篇 |
2011年 | 2492篇 |
2010年 | 1874篇 |
2009年 | 1961篇 |
2008年 | 1639篇 |
2007年 | 2340篇 |
2006年 | 2193篇 |
2005年 | 1827篇 |
2004年 | 1471篇 |
2003年 | 1314篇 |
2002年 | 1106篇 |
2001年 | 970篇 |
2000年 | 914篇 |
1999年 | 786篇 |
1998年 | 534篇 |
1997年 | 528篇 |
1996年 | 441篇 |
1995年 | 377篇 |
1994年 | 245篇 |
1993年 | 165篇 |
1992年 | 115篇 |
1991年 | 96篇 |
1990年 | 84篇 |
1989年 | 76篇 |
1988年 | 80篇 |
1987年 | 36篇 |
1986年 | 21篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 10篇 |
1981年 | 2篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1959年 | 4篇 |
1958年 | 2篇 |
1957年 | 2篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
George Ter-Stepanian 《Bulletin of Engineering Geology and the Environment》2002,61(3):197-205
The paper discusses the postulated suspension force, by which it is possible to explain some enigmatic phenomena observed
in different types of mass movements. This force is generated in thick suspensions as a result of friction between sinking
solid particles and static water. The suspension force is related to the seepage force but they have opposite directions.
Both forces form flow networks. Having explained the suspension force, the paper describes how this influences the movement
of material, particularly in debris flows. Enigmatic features and the mechanism of debris flows and lahars are explained by
virtue of the suspension force.
Electronic Publication 相似文献
32.
莱钢中小型连轧生产线技术装备状况及改进 总被引:1,自引:1,他引:0
介绍了莱钢引进的具有 90年代国际先进水平的中小型型钢连轧生产线的工艺、设备特点及主要技术参数 ,以及对原机械设备、电气及工艺备件的改进和新产品开发情况 ,均取得良好效果。 相似文献
33.
34.
摩擦强度对薄膜表面形态的作用:原子力显微镜下的观察 总被引:2,自引:2,他引:0
展示了摩擦强度对聚酰亚胺薄膜表面形态的影响,原子力显微图像显示,机械摩擦会使聚酰亚胺薄膜表面上形成微沟槽,这些沟槽的表面具有丰富的表面精细构造。原子显微图像还揭示了机械摩擦可以改变被磨擦聚酰亚胺膜的表面形态。 相似文献
35.
36.
Behaviour of a series of lubricant oils and the effect of a non stoichiometric inorganic compound, as solid extreme pressure additive, on rolling fatigue life are studied using the rolling four-ball accelerated service simulation test proposed by Barwell and Scott. The results show, in all tested cases, the remarkable efficacy of this type of additive. The Total Acidity Number (tan) was found to increase with performance time for the case of the base lubricant, while for the oils with additives, it remained at its constant low value. This led to a proposal of a possible mechanism of the additive performance in the rolling process. 相似文献
37.
Gibbs energies of formation of CoF2 and MnF2 have been measured in the temperature range from 700 to 1100 K using Al2O3-dispersed CaF2 solid electrolyte and Ni+NiF2 as the reference electrode. The dispersed solid electrolyte has higher conductivity than pure CaF2 thus permitting accurate measurements at lower temperatures. However, to prevent reaction between Al2O3 in the solid electrolyte and NiF2 (or CoF2) at the electrode, the dispersed solid electrolyte was coated with pure CaF2, thus creating a composite structure. The free energies of formation of CoF2 and MnF2 are (± 1700) J mol−1; {fx37-1} The third law analysis gives the enthalpy of formation of solid CoF2 as ΔH° (298·15 K) = −672·69 (± 0·1) kJ mol−1, which compares with a value of −671·5 (± 4) kJ mol−1 given in Janaf tables. For solid MnF2, ΔH°(298·15 K) = − 854·97 (± 0·13) kJ mol−1, which is significantly different from a value of −803·3 kJ mol−1 given in the compilation by Barinet al. 相似文献
38.
39.
采用被动式工艺生产冷轧带肋钢筋须经过减径、成型两台轧机连续轧制.要求钢材的秒流量相等,否则将造成断线停产或线材在拉丝机卷筒上打滑,致使卷筒严重磨损.用双层卷筒拉丝机提供动力生产冷轧带肋钢筋时,线材直径与卷筒直径的匹配是在一个小的调整范围,通过轧机拉力控制在一定范围变化,可保证成品尺寸符合公差要求而不产生打滑,从而避免了卷筒严重磨损. 相似文献
40.
Wang Hai-dou Xu Bin-shi Wei Shi-cheng Zhang Xian-cheng Jin Guo Jiang Yi 《中南工业大学学报(英文版)》2005,12(2):30-33
The guide-pieces, used in the process line of steel rolling, were the important components. The guidepieces, which were slide
contacting with the rolled-piece, had a high temperature and high speed. The wear was very serious. The results from failure
analysis showed that there were three failure forms in the guide-pieces: the first was the wear during heat friction, the
second was the heat fatigue under the cycle of deep heating and deep cooling, and the third was the impact rupture. Among
them, the wear was the main reason. To the wear of guidepieces, there were four mechanisms, namely abrasive wear, adhesive
wear, fatigue wear and corrosion wear. The failure analysis to the guide-piece laid the foundation for its remanufacturing.
Foundation item: Project(50235030) supported by the National Natural Science Foundation of China 相似文献