全文获取类型
收费全文 | 738篇 |
免费 | 49篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 239篇 |
金属工艺 | 9篇 |
机械仪表 | 18篇 |
建筑科学 | 27篇 |
矿业工程 | 1篇 |
能源动力 | 38篇 |
轻工业 | 73篇 |
水利工程 | 5篇 |
石油天然气 | 4篇 |
无线电 | 53篇 |
一般工业技术 | 100篇 |
冶金工业 | 26篇 |
原子能技术 | 3篇 |
自动化技术 | 184篇 |
出版年
2023年 | 8篇 |
2022年 | 19篇 |
2021年 | 32篇 |
2020年 | 20篇 |
2019年 | 33篇 |
2018年 | 27篇 |
2017年 | 21篇 |
2016年 | 25篇 |
2015年 | 18篇 |
2014年 | 37篇 |
2013年 | 50篇 |
2012年 | 42篇 |
2011年 | 46篇 |
2010年 | 42篇 |
2009年 | 37篇 |
2008年 | 34篇 |
2007年 | 33篇 |
2006年 | 34篇 |
2005年 | 28篇 |
2004年 | 22篇 |
2003年 | 32篇 |
2002年 | 17篇 |
2001年 | 10篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 9篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 10篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 8篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1972年 | 2篇 |
1963年 | 1篇 |
排序方式: 共有789条查询结果,搜索用时 15 毫秒
1.
2.
Rosendo Macias J.A. Gomez Exposito A. 《Circuits and Systems II: Express Briefs, IEEE Transactions on》2006,53(10):1098-1102
This brief presents and compares several recursive and nonrecursive techniques for the efficient computation of the running average of discrete signals. First of all, the standard recursive algorithm is considered and its long-term accuracy is assessed when the floating-point arithmetic is employed. A cheap refreshing strategy is proposed as a means of keeping the computed value close enough to the exact one. Then, two alternative nonrecursive algorithms, requiring only log2N additions, are developed, which are as reliable and accurate as the direct implementation 相似文献
3.
Vanesa Rodríguez-Amor Juan P. Fernández-Blázquez Antonio Bello Ernesto Pérez María L. Cerrada 《Polymer Bulletin》2008,60(1):89-96
Summary The effect of molecular weight on the uniaxial orientation process has been analyzed in two samples of thermotropic poly(diethylene
glycol p,p′-bibenzoate), evaluating the influence of that parameter on the type of orientation obtained. Several strain rates and deformation
temperatures have been tested in order to map out the conditions for obtaining the two different kinds of orientation. The
results show that in the lower molecular weight PDEB sample (Mw=31200) it is rather easy to get exclusively perpendicular “anomalous” orientation, with the molecular axes aligned transversely
to the stretching direction. However, it is extremely difficult to obtain 100% parallel “normal” orientation. On the contrary,
either type of orientation or a mixture of them can be easily developed for the higher molecular weight PDEB sample (Mw=102900). 相似文献
4.
5.
6.
Cruselles Ernesto J. Soriano Miguel Melús José Luis 《Wireless Personal Communications》1998,7(1):69-88
The prime characteristic of spread spectrum modulated signals is that their bandwidth is greater than the information rate. In this way a redundancy is introduced that allows the severe levels of inteference inherent in the transmission of digital information over radio and satellite links to be overcome. Current spread spectrum applications are primarily in military communications; nevertheless, there is growing interest in this technique for third generation mobile radio networks (UMTS, FPLTS, etc.) with open discussion regarding the practicality of using a multiple access system based on spread spectrum techniques (CDMA). However, in order to support as many users in the same bandwidth as other multiple access techniques such as TDMA or FDMA, it is important how to generate large families of sequences that present low cross-correlation. The aim of this paper is to describe a spreading codes generator that can produce a large number of PN sequences with good properties of auto- and cross-correlation. Moreover, the codes generated shows high unpredictability and good statistical behaviour. This also allows the implementation of some features that are common on military networks such as message privacy (increasingly important in commercial networks) without additional cost. The structure presented shows itself to be advantageous for high speed generation of codes at a low cost, low power consumption (allowing longer life for batteries), small size and simplicity of implementation, essential ingredients for commercial equipment. Another attractive feature is its structural parallelism, useful in VLSI implementations. All of these features render it potentially suitable for the implementation of channel bandwidth sharing systems in future wireless personal communications networks. 相似文献
7.
8.
This research deals with the service evaluation of a retired CrMoV steel rotor that has been repaired using deep groove multi‐pass submerged arc welding (SAW) and gas tungsten arc welding (GTAW). Accelerated creep tests were conducted at several elevated temperatures and extrapolated to the service temperatures. The coalescence of carbides and cavity growth during creep were evaluated. For the CrMoV‐GTAW samples, it was found that the creep life depended on the location of the crossweld in the welded specimen. The service lives of the weldments were extrapolated. 相似文献
9.
Exposito A.G. Soler A.B. Macias J.A. 《IEEE transactions on circuits and systems. I, Regular papers》2006,53(7):1533-1543
This paper focuses on the natural response computation of linear time-invariant (LTI) circuits, in those cases in which a closed-form solution, rather than numerical integration of the state-variable equations, is preferable. A computationally efficient procedure is presented to individually obtain the eigenvectors of matrix A, both for distinct and repeated eigenvalues. Instead of performing orthogonal matrix transformations, the proposed method relies on the solution of the nodal equations corresponding to a zero-input circuit in the generalized phasor domain. This allows propagation of natural modes to be computed by means of a simple procedure that closely resembles conventional ac analysis. 相似文献
10.
Chen Jiaoyan Hu Pan Jimenez-Ruiz Ernesto Holter Ole Magnus Antonyrajah Denvar Horrocks Ian 《Machine Learning》2021,110(7):1813-1845
Machine Learning - Semantic embedding of knowledge graphs has been widely studied and used for prediction and statistical analysis tasks across various domains such as Natural Language Processing... 相似文献