全文获取类型
收费全文 | 2346篇 |
免费 | 182篇 |
国内免费 | 64篇 |
专业分类
电工技术 | 159篇 |
综合类 | 184篇 |
化学工业 | 370篇 |
金属工艺 | 182篇 |
机械仪表 | 116篇 |
建筑科学 | 199篇 |
矿业工程 | 66篇 |
能源动力 | 70篇 |
轻工业 | 165篇 |
水利工程 | 49篇 |
石油天然气 | 137篇 |
武器工业 | 16篇 |
无线电 | 186篇 |
一般工业技术 | 292篇 |
冶金工业 | 135篇 |
原子能技术 | 26篇 |
自动化技术 | 240篇 |
出版年
2024年 | 11篇 |
2023年 | 33篇 |
2022年 | 57篇 |
2021年 | 94篇 |
2020年 | 84篇 |
2019年 | 85篇 |
2018年 | 65篇 |
2017年 | 67篇 |
2016年 | 66篇 |
2015年 | 98篇 |
2014年 | 99篇 |
2013年 | 153篇 |
2012年 | 180篇 |
2011年 | 201篇 |
2010年 | 137篇 |
2009年 | 136篇 |
2008年 | 128篇 |
2007年 | 115篇 |
2006年 | 147篇 |
2005年 | 117篇 |
2004年 | 65篇 |
2003年 | 33篇 |
2002年 | 50篇 |
2001年 | 34篇 |
2000年 | 57篇 |
1999年 | 38篇 |
1998年 | 56篇 |
1997年 | 42篇 |
1996年 | 28篇 |
1995年 | 27篇 |
1994年 | 27篇 |
1993年 | 20篇 |
1992年 | 2篇 |
1991年 | 10篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1971年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有2592条查询结果,搜索用时 46 毫秒
71.
72.
基于Internet的泵站远程状态监测与故障诊断系统研究 总被引:3,自引:0,他引:3
研究设计了基于Internet的泵站远程状态监测与故障诊断系统.系统提供了基于参数监测和仿真运行的状态监测方法,支持多种参数显示方式.水泵的各种参数被动态地监测和显示,运行状态也可以在远程状态监测计算机上进行模拟;提供了经典平稳信号分析方法和先进的非平稳信号时频分析方法用于及时诊断水泵的故障,预测运行趋势.先进的浏览器/服务器(B/S)结构在本系统得到应用,所有数据、方法和信号分析与故障诊断软件均置于服务器上.利用服务器的并行事件处理能力,可同时完成多个泵站的监测和诊断工作. 相似文献
73.
74.
摩托车脚踏座在出厂检测时发生断裂.采用断口分析方法对摩托车脚踏座的断裂原因进行了分析.结果表明,零件经过铸造工艺处理后,内部残余缩孔的存在以及魏氏组织和带状组织的出现,是造成摩托车脚踏座断裂的主要原因,表现为典型的脆性解理断裂. 相似文献
75.
Nanostructured WC-Co coatings were produced with Atmospheric Plasma Spraying (APS) and Low Pressure Plasma Spraying (LPPS). Microstructure characteristics and phase compositions of the coatings were studied by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. The microstructure compositions were analyzed with EDS. During APS deposition the existence of oxygen causes the decarburization of the coating, and the coating was composed of melted area and the WC/12Co powder. Besides WC phase, there was W2C phase. However in the coating deposited by LPPS the content of oxygen was so low that there were a limit degradation of the WC/12Co powder. The coatings were made up of compact block and loosen porosity area. There were large quantities of nanostructure WC grains and a small quantity of microstructure WC grains presented in the coating. Besides WC phase, a little W2C and WC1-x or Co6W6C phases occured. Consideration of the characteristics of the highly porous, spherical-shell morphology of nano-WC/12Co power, heterogeneous melting and localized superheating of the power were two main factors which caused the microstructure and phase composition of nano-WC-Co coatings. 相似文献
76.
The Al-27%Si alloy was prepared by the spray forming process, and its microstructure evolution during the semisolid reheating process was investigated. The results show that, the primary Si phase coarsens during the reheating process and the coarsening rate increases with the increase of reheating temperature. The eutectic phase is produced in the molten region when quenched in the cold water. The microstructure evolution in the semisolid state can be divided into three stages. The remarkable characteristic of the first stage is only a solid-state phase transformation process. However, the region around the α(Al) matrix gradually melts in the second stage. The primary Si in the liquid phase coarsens obviously, and the eutectic phase is produced in the molten region when the specimens are quenched in cold water. In the last stage, the same thing as that in the second stage happens except that all the α(Al) matrixes are melted. 相似文献
77.
结合工程实例,简单阐述酸性水罐的氮封系统设计。本设计采用安全水封罐确保酸性水罐压力,通过脱臭罐排放硫化氢气体;在脱臭罐出现事故情况下则通过安全水封罐排放硫化氢气体。该流程与储运常规氮风系统流程相比,更加安全可靠,更有利于减少环境污染。 相似文献
78.
In this article, a terpolymer of ethylene, maleic anhydride, and glycidyl methacrylate (EMG) was used to enhance the compatibilization between poly(phenylene sulfide) (PPS) and polyamide‐66 (PA66). The mechanical properties, morphology, crystalline and melting behavior, and rheology of blends were discussed. The results showed that EMG was a good compatibilizer for PPS and PA66 through chemical reaction with them. The new generated polymer could prevent the aggregation of dispersed particles and reinforce the interface bonding. In addition, it could not only act as a nucleating agent for PA66 to refine its spherulites and improve its crystallinity but also promote the apparent viscosity of blends and enhance the non‐Newtonian behavior. The results will be useful to make high performance PPS/PA66 alloy with low cost and enlarge the application scope of PPS and PA66 resin. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
79.
Li Yafeng Nie Rusong Leng Wuming Guo Yipeng Dong Junli Sun Baoli 《Bulletin of Engineering Geology and the Environment》2021,80(4):3079-3096
Bulletin of Engineering Geology and the Environment - The long-term loading of the trains on the subgrade in service is the cyclic loading when the train passes and the intermittent stage when... 相似文献
80.
Zhang Ke Mao Yuming Leng Supeng Maharjan Sabita Vinel Alexey Zhang Yan 《Mobile Networks and Applications》2019,24(3):1003-1014
Mobile Networks and Applications - Mobile Edge Computing (MEC) is a promising solution to improve vehicular services through offloading computation to cloud servers in close proximity to mobile... 相似文献