全文获取类型
收费全文 | 84831篇 |
免费 | 7730篇 |
国内免费 | 5045篇 |
专业分类
电工技术 | 5397篇 |
技术理论 | 1篇 |
综合类 | 8493篇 |
化学工业 | 12761篇 |
金属工艺 | 4703篇 |
机械仪表 | 5534篇 |
建筑科学 | 5949篇 |
矿业工程 | 2115篇 |
能源动力 | 2254篇 |
轻工业 | 7916篇 |
水利工程 | 1888篇 |
石油天然气 | 3253篇 |
武器工业 | 809篇 |
无线电 | 10116篇 |
一般工业技术 | 8678篇 |
冶金工业 | 3556篇 |
原子能技术 | 1136篇 |
自动化技术 | 13047篇 |
出版年
2024年 | 288篇 |
2023年 | 998篇 |
2022年 | 2016篇 |
2021年 | 2718篇 |
2020年 | 2130篇 |
2019年 | 1762篇 |
2018年 | 1896篇 |
2017年 | 2239篇 |
2016年 | 2180篇 |
2015年 | 3111篇 |
2014年 | 4163篇 |
2013年 | 4963篇 |
2012年 | 5976篇 |
2011年 | 6393篇 |
2010年 | 6068篇 |
2009年 | 5988篇 |
2008年 | 5959篇 |
2007年 | 5873篇 |
2006年 | 5466篇 |
2005年 | 4585篇 |
2004年 | 3708篇 |
2003年 | 3178篇 |
2002年 | 3698篇 |
2001年 | 3250篇 |
2000年 | 2243篇 |
1999年 | 1536篇 |
1998年 | 954篇 |
1997年 | 805篇 |
1996年 | 723篇 |
1995年 | 630篇 |
1994年 | 460篇 |
1993年 | 343篇 |
1992年 | 275篇 |
1991年 | 210篇 |
1990年 | 176篇 |
1989年 | 115篇 |
1988年 | 111篇 |
1987年 | 82篇 |
1986年 | 38篇 |
1985年 | 55篇 |
1984年 | 42篇 |
1983年 | 33篇 |
1982年 | 21篇 |
1981年 | 22篇 |
1980年 | 23篇 |
1979年 | 17篇 |
1977年 | 12篇 |
1976年 | 15篇 |
1959年 | 8篇 |
1951年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Shane Y. Hong 《Journal of Intelligent Manufacturing》1993,4(3):233-241
One major bottleneck in the automation of the drilling process by robots in the aerospace industry is drill condition monitoring. This paper describes a system approach to solve this problem through the advancement of new machine design, sensor instrumentation, metal-cutting research, and intelligent software development. All drill failures can be detected and distinguished: chisel edge wear, flank wear, crater wear, margin wear, corner wear, breakage, asymmetry, lip height difference, and chipping at lips. However, in the real manufacturing environment, different workpiece materials, drill size, drill geometry, drill material, cutting speed, feed rate, etc. will change the criteria for judging the drill condition. The knowledge base used for diagnosing the drill failures requires a huge data bank and prior exhaustive testing. A self-learning scheme is therefore introduced to the machine in order to acquire the threshold history needed for automatic diagnosis by using the same new tool under the same drilling conditions. 相似文献
42.
ElectrochemicalInvestigationontheFormationofDyFeAloyinMoltenChloridesLiuGuankun(刘冠昆),TongYexiang(童叶翔),HongHuichan(洪惠婵),Yang... 相似文献
43.
44.
45.
Bor -Yir Chen Wei -Hsiung Wu Jiann -Ruey Chen Chum -Sam Hong 《Journal of Materials Science》1995,30(9):2254-2256
The temperature dependence characteristics of hydrogenated amorphous silicon thin-film transistors were investigated. The results indicate that as the temperature was increased, the threshold voltage and the field-effect mobility were first increased, and then decreased, which may be controlled by different mechanisms at low and high temperatures. In addition, if the temperature was higher than 420 K, the Fermi level was promoted to the degenerate-like states, the current channel always existed due to the temperature effect, and the threshold voltage became negative. 相似文献
46.
47.
介绍当今冶金机械齿轮传动装置制造技术水平,以及大型齿轮传动装置齿轮制造工艺参数选择,从中探索研究冶金机械齿轮传动装置发展趋势. 相似文献
48.
A new model, based on Seetharaman’s viscosity model and Chou’s geometric-thermodynamic model, to predict the viscosity of
ternary-metallic melts has been established. The viscosities of Ag-Au-Cu and Ag-Sn-Cu systems have been calculated with the
present model, and the results are consistent with the experimental data. The viscosities of Au-Ni-Cu, Fe-Ni-Cu, Al-Sn-Cu,
and In-Sn-Bi systems have also been predicted by the present model. 相似文献
49.
Tang Y.Y. Hong Ma Jiming Liu Bing Fa Li Dihua Xi 《IEEE transactions on pattern analysis and machine intelligence》1997,19(8):921-926
Based on wavelets, a theoretical method has been developed to process multi-gray level documents. In this method, two-dimensional multiresolution analysis, a wavelet decomposition algorithm, and compactly supported orthonormal wavelets are used to transform a document image into sub-images. According to these sub-images, the reference lines of a multi-gray level document can be extracted, and knowledge about the geometric structure of the document can be acquired. Particularly, this approach is more efficient to process form documents with gray level background. Experiments indicate that this new method can be applied to process documents with promising results 相似文献
50.