全文获取类型
收费全文 | 71105篇 |
免费 | 6089篇 |
国内免费 | 4033篇 |
专业分类
电工技术 | 4206篇 |
技术理论 | 1篇 |
综合类 | 6908篇 |
化学工业 | 11070篇 |
金属工艺 | 3874篇 |
机械仪表 | 4493篇 |
建筑科学 | 4929篇 |
矿业工程 | 1631篇 |
能源动力 | 1902篇 |
轻工业 | 6346篇 |
水利工程 | 1462篇 |
石油天然气 | 2798篇 |
武器工业 | 546篇 |
无线电 | 8535篇 |
一般工业技术 | 7556篇 |
冶金工业 | 3033篇 |
原子能技术 | 980篇 |
自动化技术 | 10957篇 |
出版年
2024年 | 217篇 |
2023年 | 760篇 |
2022年 | 1457篇 |
2021年 | 2057篇 |
2020年 | 1626篇 |
2019年 | 1460篇 |
2018年 | 1562篇 |
2017年 | 1800篇 |
2016年 | 1788篇 |
2015年 | 2488篇 |
2014年 | 3365篇 |
2013年 | 4066篇 |
2012年 | 4818篇 |
2011年 | 5193篇 |
2010年 | 4916篇 |
2009年 | 4857篇 |
2008年 | 4861篇 |
2007年 | 4656篇 |
2006年 | 4567篇 |
2005年 | 3832篇 |
2004年 | 3157篇 |
2003年 | 2834篇 |
2002年 | 3399篇 |
2001年 | 2958篇 |
2000年 | 2016篇 |
1999年 | 1447篇 |
1998年 | 942篇 |
1997年 | 785篇 |
1996年 | 708篇 |
1995年 | 615篇 |
1994年 | 451篇 |
1993年 | 333篇 |
1992年 | 266篇 |
1991年 | 205篇 |
1990年 | 172篇 |
1989年 | 108篇 |
1988年 | 106篇 |
1987年 | 78篇 |
1986年 | 32篇 |
1985年 | 52篇 |
1984年 | 41篇 |
1983年 | 31篇 |
1982年 | 19篇 |
1981年 | 19篇 |
1980年 | 18篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1977年 | 12篇 |
1976年 | 15篇 |
1951年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
研究了铁钴钒软磁合金的铁芯损耗,发现铁芯损耗谱具有分形结构。讨论了带材厚度和磁感应强度对分形维数Df的影响。 相似文献
53.
For pt.I see IEEE Trans. Neural Networks, vol.1, p.167-78 (1990). Parallel, self-organizing, hierarchical neural networks (PSHNNs) involve a number of stages with error detection at the end of each stage, i.e., rejection of error-causing vectors, which are then fed into the next stage after a nonlinear transformation. The stages operate in parallel during testing. Statistical properties and the mechanisms of vector rejection of the PSHNN are discussed in comparison to the maximum likelihood method and the backpropagation network. The PSHNN is highly fault tolerant and robust against errors in the weight values due to the adjustment of the error detection bounds to compensate errors in the weight values. These properties are exploited to develop architectures for programmable implementations in which the programmable parts are reduced to on-off or bipolar switching operations for bulk computations and attenuators for pointwise operations 相似文献
54.
Jun-Hee Hong Jong-Keun Park 《Power Systems, IEEE Transactions on》1995,10(4):1789-1797
This paper presents a method of obtaining transmission network equivalents from the network's response to a pulse excitation signal. The proposed method is based on modal decomposition representation for the large-scale interconnected system. In this framework we use Prony analysis to identify the network function of the system and to decompose the large system into a parallel combination of simple first-order systems. As a result the network function of the transmission network can be identified easily, and a Thevenin-type of discrete-time filter model can be generated. It can reproduce the driving-point impedance characteristic of the network. Furthermore, the proposed model can be implemented into the EMTP in a direct manner. The simulation results with the full system representation and the developed equivalent system showed a good agreement 相似文献
55.
56.
57.
58.
Gunapala S.D. Bundara S.V. Liu J.K. Winn Hong Mani Sundaram Maker P.D. Muller R.E. Shott C.A. Carralejo R. 《Electron Devices, IEEE Transactions on》1998,45(9):1890-1895
A 9-μm cutoff 640×486 snap-shot quantum well infrared photodetector (QWIP) camera has been demonstrated. The performance of this QWIP camera is reported including indoor and outdoor imaging. The noise equivalent differential temperature (NEΔT) of 36 mK has been achieved at 300 K background with f/2 optics. This is in good agreement with expected focal plane array sensitivity due to the practical limitations on charge handling capacity of the multiplexer, read noise, bias voltage, and operating temperature 相似文献
59.
60.
Motoharu Fujigaki In Hong Yang Yoshiharu Morimoto Eung Kyo Han 《NDT & E International》1996,29(4):197-203
There is no good method to measure the shape and the strain distributions of a structure changing with time. We have previously proposed the Fourier transform grid method (FTGM) to measure the three-dimensional shape and surface strain distributions of stationary objects by analysing the two-dimensional grating images recorded with two cameras. In the stereoscopic method, it is very important to determine the accurate geometric parameters of the camera system. In this paper, the positions and the directions of cameras are accurately determined using the FTGM applied to images of a reference object on which a two-dimensional grating is drawn. Applications for analysing shape and strain distributions of vibrating rubber plates and a moving human skin are shown. 相似文献