全文获取类型
收费全文 | 3926篇 |
免费 | 625篇 |
国内免费 | 425篇 |
专业分类
电工技术 | 474篇 |
综合类 | 517篇 |
化学工业 | 36篇 |
金属工艺 | 69篇 |
机械仪表 | 314篇 |
建筑科学 | 39篇 |
矿业工程 | 95篇 |
能源动力 | 46篇 |
轻工业 | 17篇 |
水利工程 | 27篇 |
石油天然气 | 32篇 |
武器工业 | 34篇 |
无线电 | 1238篇 |
一般工业技术 | 196篇 |
冶金工业 | 24篇 |
原子能技术 | 8篇 |
自动化技术 | 1810篇 |
出版年
2024年 | 13篇 |
2023年 | 46篇 |
2022年 | 70篇 |
2021年 | 83篇 |
2020年 | 100篇 |
2019年 | 80篇 |
2018年 | 73篇 |
2017年 | 133篇 |
2016年 | 138篇 |
2015年 | 190篇 |
2014年 | 280篇 |
2013年 | 278篇 |
2012年 | 331篇 |
2011年 | 368篇 |
2010年 | 330篇 |
2009年 | 297篇 |
2008年 | 319篇 |
2007年 | 345篇 |
2006年 | 308篇 |
2005年 | 292篇 |
2004年 | 223篇 |
2003年 | 165篇 |
2002年 | 146篇 |
2001年 | 121篇 |
2000年 | 65篇 |
1999年 | 36篇 |
1998年 | 22篇 |
1997年 | 24篇 |
1996年 | 27篇 |
1995年 | 27篇 |
1994年 | 11篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有4976条查询结果,搜索用时 62 毫秒
121.
122.
This paper addresses the stabilization problem for a class of nonlinear systems. It is assumed that the
controller can only receive the transmitted sequence of finite coded signals via a limited digital communication channel.
Both state and output feedback coder-decoder-controller procedures are proposed. Stabilization conditions involving the
size of coding alphabet, the sampling period, system state growth rate and data packet dropout rate are obtained. Finally,
an example is given to illustrate the design procedures and effectiveness of the proposed results. 相似文献
123.
无线传感器网络作为一种新兴的技术具有广泛的研究价值和实际应用价值。设计并实现了一个多频段的无线传感器网络实验平台。该平台包括2.4GHz和433MHz的两个子网。两个子网分别通过网关与PC机相连,PC机完成对不同子网的数据包分析和解包,并可对各子网下达指令。实验结果表明,该平台能够完成胜任一般实验的需求,对于理论研究和实际应用都具有十分重要的意义。 相似文献
124.
125.
126.
Chi-man Vong Pak-kin Wong Weng-fai Ip 《Engineering Applications of Artificial Intelligence》2011,24(7):1281-1294
Whenever there is any fault in an automotive engine ignition system or changes of an engine condition, an automotive mechanic can conventionally perform an analysis on the ignition pattern of the engine to examine symptoms, based on specific domain knowledge (domain features of an ignition pattern). In this paper, case-based reasoning (CBR) approach is presented to help solve human diagnosis problem using not only the domain features but also the extracted features of signals captured using a computer-linked automotive scope meter. CBR expert system has the advantage that it provides user with multiple possible diagnoses, instead of a single most probable diagnosis provided by traditional network-based classifiers such as multi-layer perceptions (MLP) and support vector machines (SVM). In addition, CBR overcomes the problem of incremental and decremental knowledge update as required by both MLP and SVM. Although CBR is effective, its application for high dimensional domains is inefficient because every instance in a case library must be compared during reasoning. To overcome this inefficiency, a combination of preprocessing methods, such as wavelet packet transforms (WPT), kernel principal component analysis (KPCA) and kernel K-means (KKM) is proposed. Considering the ignition signals captured by a scope meter are very similar, WPT is used for feature extraction so that the ignition signals can be compared with the extracted features. However, there exist many redundant points in the extracted features, which may degrade the diagnosis performance. Therefore, KPCA is employed to perform a dimension reduction. In addition, the number of cases in a case library can be controlled through clustering; KKM is adopted for this purpose. In this paper, several diagnosis methods are also used for comparison including MLP, SVM and CBR. Experimental results showed that CBR using WPT and KKM generated the highest accuracy and fitted better the requirements of the expert system. 相似文献
127.
Yi-Yan Liu Yong-Feng JuChen-Dong Duan Xue-Feng Zhao 《Engineering Applications of Artificial Intelligence》2011,24(1):87-92
A structure damage diagnosis method combining the wavelet packet decomposition, multi-sensor feature fusion theory and neural network pattern classification was presented. Firstly, vibration signals gathered from sensors were decomposed using orthogonal wavelet. Secondly, the relative energy of decomposed frequency band was calculated. Thirdly, the input feature vectors of neural network classifier were built by fusing wavelet packet relative energy distribution of these sensors. Finally, with the trained classifier, damage diagnosis and assessment was realized. The result indicates that, a much more precise and reliable diagnosis information is obtained and the diagnosis accuracy is improved as well. 相似文献
128.
针对浊音、清音和噪声的不同特性,结合听觉掩蔽并使用随尺度变化的多阈值对语音信号进行处理.提出了多小波门限估计法,该方法针对不同声音成分,使用不同的与尺度有关的缩小因子调节门限值;通过估计各频带内的信噪比,实现了阈值的时频自适应变化;用巴克小波包分解法模拟人耳临界带特性,用小波谱减法对带噪语音进行预增强,采用Johnst... 相似文献
129.
130.