全文获取类型
收费全文 | 20327篇 |
免费 | 3753篇 |
国内免费 | 2540篇 |
专业分类
电工技术 | 1021篇 |
综合类 | 2066篇 |
化学工业 | 989篇 |
金属工艺 | 362篇 |
机械仪表 | 1187篇 |
建筑科学 | 214篇 |
矿业工程 | 217篇 |
能源动力 | 92篇 |
轻工业 | 344篇 |
水利工程 | 102篇 |
石油天然气 | 386篇 |
武器工业 | 283篇 |
无线电 | 4241篇 |
一般工业技术 | 1197篇 |
冶金工业 | 950篇 |
原子能技术 | 41篇 |
自动化技术 | 12928篇 |
出版年
2024年 | 171篇 |
2023年 | 434篇 |
2022年 | 902篇 |
2021年 | 1029篇 |
2020年 | 1015篇 |
2019年 | 732篇 |
2018年 | 617篇 |
2017年 | 741篇 |
2016年 | 841篇 |
2015年 | 893篇 |
2014年 | 1304篇 |
2013年 | 1160篇 |
2012年 | 1470篇 |
2011年 | 1587篇 |
2010年 | 1297篇 |
2009年 | 1332篇 |
2008年 | 1391篇 |
2007年 | 1520篇 |
2006年 | 1341篇 |
2005年 | 1142篇 |
2004年 | 938篇 |
2003年 | 869篇 |
2002年 | 708篇 |
2001年 | 483篇 |
2000年 | 412篇 |
1999年 | 379篇 |
1998年 | 312篇 |
1997年 | 242篇 |
1996年 | 185篇 |
1995年 | 177篇 |
1994年 | 139篇 |
1993年 | 135篇 |
1992年 | 109篇 |
1991年 | 52篇 |
1990年 | 48篇 |
1989年 | 67篇 |
1988年 | 42篇 |
1987年 | 25篇 |
1986年 | 24篇 |
1985年 | 33篇 |
1984年 | 34篇 |
1983年 | 43篇 |
1982年 | 38篇 |
1981年 | 33篇 |
1980年 | 27篇 |
1979年 | 22篇 |
1978年 | 23篇 |
1977年 | 26篇 |
1976年 | 23篇 |
1974年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Ravaja Niklas; Kallinen Kari; Saari Timo; Keltikangas-Jarvinen Liisa 《Canadian Metallurgical Quarterly》2004,10(2):120
The authors examined the effects of suboptimally presented facial expressions on emotional and attentional responses and memory among 39 young adults viewing video (business news) messages from a small screen. Facial electromyography (EMG) and respiratory sinus arrhythmia were used as physiological measures of emotion and attention, respectively. Several congruency priming effects were found. In particular, happy facial primes prompted increased (a) pleasure ratings, (b) orbicularis oculi EMG activity, (c) perceived trustworthiness, and (d) recognition memory for video messages with a positive emotional tone. Emotional and other responses to video messages presented on a small screen can be modified with suboptimal affective primes, but even small differences in the emotional tone of the messages should be allowed for. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
102.
Moritoshi Yasunaga Noriyuki Aibe Yoshiki Yamaguchi Yorihisa Yamamoto Takaaki Awano Ikuo Yoshihara 《Artificial Life and Robotics》2008,12(1-2):219-222
Watching and tracking an object while seeing a much wider view is one of advantages of the eye system. We proposed and developed
a tracking camera system that mimics the eyes by using double-lens modules. In the system, a wide view is captured through
the wide-lens module, while the target in it is tracked and magnified through the telescopic lens module. Electronic circuits
for tracking control are implemented onto the reconfigurable VLSI or FPGA in order to embed the parallelism in the tracking
algorithm into the hardware. A successfully developed FPGA-based prototype performs high-speed tracking at the video-rate.
This work was present in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27,
2007 相似文献
103.
Theorists have predicted that repetition blindness (RB) should be absent for nonwords because they do not activate preexisting mental types. The authors hypothesized that RB would be observed for nonwords because RB can occur at a sublexical level. Four experiments showed that RB is observed for word-nonword pairs (noon noof), orthographically similar nonwords (glome glame), and identical repetitions (plass plass). More RB was found for words than for nonwords. Prior researchers may have failed to find RB for nonwords because display conditions that allow 2 words to be reliably encoded are insufficient for nonwords, or because observers coped with low ability to encode nonwords by using guessing strategies that do not require creating a mental type or tokenizing it. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
104.
A model-based autotuning method consists of an identification and a regulator tuning phase. To achieve satisfactory performance and robustness, it is advisable that both phases be tailored a priori to the characteristics of the observed process dynamics. Such characteristics include, but are not limited to, the model structure. For example, overdamped and underdamped models with the same pole-zero structure are parametrised and controlled in different ways. Step response data, that are typically used for the identification phase in the autotuning context, can also be pre-processed to reveal those characteristics. This paper presents a step response classification method suitable for the above purpose. The method is based on a polygonal curve approximation technique for data pre-processing, followed by a neural network classifier. Only normalised I/O data are employed, so that the neural network can be trained off-line with simulated data. Simulation results are reported to show the effectiveness of the proposed classification method in terms of the achievable tuning results. 相似文献
105.
We propose subspace distance measures to analyze the similarity between intrapersonal face subspaces, which characterize the variations between face images of the same individual. We call the conventional intrapersonal subspace average intrapersonal subspace (AIS) because the image differences often come from a large number of persons. An intrapersonal subspace is referred to as specific intrapersonal subspace (SIS) if the image differences are from just one person. We demonstrate that SIS varies significantly from person to person, and most SISs are not similar to AIS. Based on these observations, we introduce the maximum a posteriori (MAP) adaptation to the problem of SIS estimation, and apply it to the Bayesian face recognition algorithm. Experimental results show that the adaptive Bayesian algorithm outperforms the non-adaptive Bayesian algorithm as well as Eigenface and Fisherface methods if a small number of adaptation images are available. 相似文献
106.
Qijun Zhao 《Pattern recognition》2006,39(2):310-312
In this paper, we propose a fast Evolutionary pursuit algorithm. It searches for optimal discriminant vectors through linearly combining standard bases. Experiments on the Yale and ORL databases verify its effectiveness and enhanced efficiency. 相似文献
107.
108.
介绍一种利用径向矢量提取形状特征的方法,着重于分析二维图形的不变性,提出一种带有方向因子的径向矢量描述,该矢量以图形边界弧长为自变量,完整地刻画了图形特点,克服了非凸图形识别中存在的多义性,以归一化的特征矢量的输入,采用三层神经网络为分类器,在字符及军事目标不变性识别中取得了令人满意的结果。 相似文献
109.
化学模式识别法在钢铁工业中的若干应用 总被引:1,自引:0,他引:1
本文涉及一种崭新的非函数数据处理法及其在工业诊断和优化中的应用。并对其进行要因分析和优化决策的原理作了介绍。结合钢铁工业生产中的实例进行了分析。还探讨了该方法在钢铁工业中应用的意义。 相似文献
110.
Gerardo Gabriel Acosta Miguel Angel Mayosky José Maria Catalfo 《Applied Intelligence》1994,4(1):53-66
This article proposes a scheme for the on-line adjustment of three mode controller settings based on experimental measurements of closed-loop performance. It uses a recently developed heuristic tuning procedure to identify estimated process parameters. This method may give rise to conflicting estimates. Fuzzy Set theory is applied to manage the situation in terms of a fuzzy conjunction to combine the various estimates. PID control was chosen because of its wide use in the industrial environment due to driving simplicity and robustness. The article shows design, development, and computer simulation aspects. 相似文献