全文获取类型
收费全文 | 31674篇 |
免费 | 3588篇 |
国内免费 | 1679篇 |
专业分类
电工技术 | 9751篇 |
技术理论 | 1篇 |
综合类 | 2909篇 |
化学工业 | 1198篇 |
金属工艺 | 722篇 |
机械仪表 | 2196篇 |
建筑科学 | 1324篇 |
矿业工程 | 847篇 |
能源动力 | 790篇 |
轻工业 | 288篇 |
水利工程 | 554篇 |
石油天然气 | 555篇 |
武器工业 | 483篇 |
无线电 | 8646篇 |
一般工业技术 | 1390篇 |
冶金工业 | 567篇 |
原子能技术 | 301篇 |
自动化技术 | 4419篇 |
出版年
2024年 | 124篇 |
2023年 | 447篇 |
2022年 | 722篇 |
2021年 | 944篇 |
2020年 | 989篇 |
2019年 | 783篇 |
2018年 | 610篇 |
2017年 | 903篇 |
2016年 | 1068篇 |
2015年 | 1202篇 |
2014年 | 2059篇 |
2013年 | 1770篇 |
2012年 | 2355篇 |
2011年 | 2485篇 |
2010年 | 1979篇 |
2009年 | 1936篇 |
2008年 | 1896篇 |
2007年 | 2305篇 |
2006年 | 2078篇 |
2005年 | 1707篇 |
2004年 | 1460篇 |
2003年 | 1301篇 |
2002年 | 1040篇 |
2001年 | 932篇 |
2000年 | 822篇 |
1999年 | 567篇 |
1998年 | 395篇 |
1997年 | 363篇 |
1996年 | 353篇 |
1995年 | 282篇 |
1994年 | 256篇 |
1993年 | 178篇 |
1992年 | 149篇 |
1991年 | 108篇 |
1990年 | 83篇 |
1989年 | 82篇 |
1988年 | 70篇 |
1987年 | 26篇 |
1986年 | 18篇 |
1985年 | 18篇 |
1984年 | 22篇 |
1983年 | 13篇 |
1982年 | 11篇 |
1981年 | 4篇 |
1980年 | 9篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1956年 | 1篇 |
1951年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The relation between the initial unbalance and the output signal of bridge circuits when acted upon simultaneously by the
physical factor being measured and the temperature of the surroundings when the bridge is supplied from a voltage or current
source is investigated. Analytic relations are obtained which explain the temperature dependence of the useful output voltage
under external physical action.
__________
Translated from Izmeritel’naya Tekhnika, No. 1, pp. 48–49, 2007. 相似文献
82.
世界及我国电解铜箔业的发展回顾 总被引:4,自引:0,他引:4
印制电路板用电解铜箔产品在世界上已经历了近五十年的发展历程。本文从电解铜箔的生产、市场、技术等方面,记述、回顾了世界及我国的发展过程和有关的重要事件。 相似文献
83.
蒋艳兰 《有色冶金设计与研究》2003,(Z1)
介绍了Farad2 0 0SEA变电站综合自动化系统在中铝广西分公司热电厂的配置、功能及应用情况 ,着重阐述了系统的网络结构组成。 相似文献
84.
Argyris G. Kagiannas Thanassis Didis Dimitris Th. Askounis John Psarras 《国际能源研究杂志》2003,27(2):173-186
The needs that an energy supply system must meet are constantly changing, due to technological, social and political reasons. Effective energy planning is a dynamic process that is repeated periodically and adjusts to changing conditions. Energy decision makers and planners are no longer able to rely on inductive decision making since they have to investigate the effect of various decision parameters and possible future changes. To help in this process, models have been developed where estimates of future load growth, candidate power plants, fuels and other key factors can be introduced, from which the planners can evaluate decision parameters and the available alternatives. The paper presents the different methodologies and practices that are used by 11 energy models for energy demand forecasting, supply side management and generation expansion planning, demand side management and integrated resource planning. The paper concludes to the presentation of a strategic appraisal of the examined energy models appropriate for energy planning in Mozambique. Three models are proposed for conducting demand forecasting, generation expansion planning and demand side management. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
85.
86.
通过对现代海上电子战特点深刻探讨。分析了现代海战条件对舰船电子战对抗能力需求。并对现代舰船电子战综合对抗系统所采用的新技术情况进行探讨。 相似文献
87.
Syed M. Alam Donald E. Troxel Carl V. Thompson 《Analog Integrated Circuits and Signal Processing》2003,35(2-3):199-206
In this paper, we describe a comprehensive layout methodology for bonded three-dimensional integrated circuits (3D ICs). In bonded 3D integration technology, parts of a circuit are fabricated on different wafers, and then, the wafers are bonded with a glue layer of Cu or polymer based adhesive. Using our layout methodology, designers can layout such 3D circuits with necessary information on inter-wafer via/contact and orientation of each wafer embedded in the layout. We have implemented the layout methodology in 3DMagic. Availability of 3DMagic has led to interesting research with a wide range of layout-specific circuit evaluation, from performance comparison of 2D and 3D circuits to layout-specific reliability analyses in 3D circuits. Using 3DMagic, researchers have designed and simulated an 8-bit encryption processor mapped into 2D and 3D FPGA layouts. Moreover, the layout methodology is an essential element of our ongoing research for the framework of a novel Reliability Computer Aided Design tool, ERNI-3D. 相似文献
88.
89.
金属包覆平板波导模式特性的有限元法分析 总被引:2,自引:0,他引:2
采用有限元法(FEM)分析了具有复数折射率的金属包覆介质波导的模折射率与模场分布情况。计算了具有损耗层的6层介质平板波导模折射率,并与解析解比较,二者有较好的一致性;分析了金属包覆3层平板波导中TM模折射率与波导芯厚度的变化关系,计算了金属包覆5层平板波导中TM模折秧经与金属层厚度的变化关系,并结合对模场分布的分析对模式进行了定性判断,给出了其模式演变过程。 相似文献
90.
It is necessary to determine the accurate reflectance of painted surfaces for the review of paint finishes by computer graphics (CG) before actual painting of the exterior color of automobiles, and for quality control during production and inspection processes. We have optimized a method for measuring reflectance by using a statistical technique. We have found that the reflectance of a painted surface is best measured at an incident angle of 60° and at five aspecular angles of 10°, 18°, 28°, 40°, and 90°. Our method makes it possible to accurately reproduce reflection characteristics of paint finishes containing special flake pigments, such as pearl mica. Also it was proved that our method can apply not only to solid and metallic coatings but to all painted surfaces. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 275–282, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20125 相似文献