全文获取类型
收费全文 | 57574篇 |
免费 | 2860篇 |
国内免费 | 197篇 |
专业分类
电工技术 | 881篇 |
综合类 | 94篇 |
化学工业 | 10863篇 |
金属工艺 | 2137篇 |
机械仪表 | 3169篇 |
建筑科学 | 1283篇 |
矿业工程 | 52篇 |
能源动力 | 2232篇 |
轻工业 | 4142篇 |
水利工程 | 259篇 |
石油天然气 | 210篇 |
武器工业 | 1篇 |
无线电 | 10199篇 |
一般工业技术 | 11575篇 |
冶金工业 | 5884篇 |
原子能技术 | 642篇 |
自动化技术 | 7008篇 |
出版年
2023年 | 514篇 |
2022年 | 611篇 |
2021年 | 1436篇 |
2020年 | 1021篇 |
2019年 | 1050篇 |
2018年 | 1390篇 |
2017年 | 1387篇 |
2016年 | 1707篇 |
2015年 | 1361篇 |
2014年 | 2104篇 |
2013年 | 3592篇 |
2012年 | 3282篇 |
2011年 | 4050篇 |
2010年 | 3076篇 |
2009年 | 3262篇 |
2008年 | 3004篇 |
2007年 | 2531篇 |
2006年 | 2298篇 |
2005年 | 1983篇 |
2004年 | 1879篇 |
2003年 | 1733篇 |
2002年 | 1685篇 |
2001年 | 1313篇 |
2000年 | 1217篇 |
1999年 | 1195篇 |
1998年 | 2214篇 |
1997年 | 1447篇 |
1996年 | 1209篇 |
1995年 | 967篇 |
1994年 | 726篇 |
1993年 | 692篇 |
1992年 | 493篇 |
1991年 | 498篇 |
1990年 | 417篇 |
1989年 | 408篇 |
1988年 | 323篇 |
1987年 | 277篇 |
1986年 | 260篇 |
1985年 | 234篇 |
1984年 | 203篇 |
1983年 | 154篇 |
1982年 | 153篇 |
1981年 | 130篇 |
1980年 | 129篇 |
1979年 | 102篇 |
1978年 | 94篇 |
1977年 | 126篇 |
1976年 | 162篇 |
1975年 | 80篇 |
1974年 | 75篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
951.
E. W. M. Lee I. W. H. Fung V. W. Y. Tam M. Arashpour 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2014,18(10):1999-2014
Building cooling load prediction is critical to the success of energy-saving measures. While many of the computational models currently available in the industry have been developed for this purpose, most require extensive computer resources and involve lengthy computational processes. Artificial neural networks (ANNs) have recently been adopted for prediction, and pioneering works have confirmed the feasibility of this approach. However, users are required to predetermine an ANN model’s parameters. This hinders the applicability of the ANN approach in actual engineering problems, as most engineers may be unfamiliar with soft computing. This paper proposes a fully autonomous kernel-based neural network (AKNN) model for noisy data regression prediction. No part of the model’s mechanism requires human intervention; rather, it self-organises its structure according to the training samples presented. Unlike the other existing autonomous models, the AKNN model is an online learning model. It is particularly suitable for online steps-ahead prediction. In this paper, we benchmark the AKNN model’s performance according to other ANN models. It is also successfully applied to predicting the cooling load of a commercial building in Hong Kong. The occupancy areas and concentration of carbon dioxide inside the building are successfully adopted to mimic the building’s internal cooling load. Training data was adopted from actual measurements taken inside the building. Its results show reasonable agreement with actual cooling loads. 相似文献
952.
In this paper, a real-time stochastic optimal control method of traffic signal is modified. In addition, H-GA-PSO algorithm is proposed to search optimal traffic signals based on the stochastic model. The H-GA-PSO algorithm is a modified Hierarchical Particle Swarm Optimization (H-PSO) algorithm based on Genetic Algorithm (GA) processing. Finally, the effectiveness of the stochastic optimal control method with H-GA-PSO algorithm is shown through simulations at multiple intersections using a micro-traffic simulator. 相似文献
953.
SVD‐Based Accurate Identification and Compensation of the Coupling Hysteresis and Creep Dynamics in Piezoelectric Actuators
下载免费PDF全文
![点击此处可从《Asian journal of control》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Tong Heng Lee 《Asian journal of control》2014,16(1):59-69
In this paper, the coupling hysteresis and creep in piezoelectric actuators are identified and compensated for accurate tracking. First, we present the coupling hysteresis and creep model in smart actuators. Next, a complete identification strategy is designed according to the properties of the Preisach model. Then, an approach for parameter updating of the coupling model is provided. With the identified hysteresis and creep, the model‐based inversion compensation is designed. Finally, we apply the model identification and compensation to a piezoelectric stage to demonstrate the effectiveness of the proposed approaches. Significant reduction of the tracking error is achieved with the model‐based inversion feedforward compensator in which the relative errors at 10 Hz and 50 Hz are reduced to 1.85% and 4.53%, respectively. In addition, the model‐based feedforward is augmented with an integral feedback controller. With the composite controller, the relative errors at 10 Hz and 50 Hz are reduced to 0.42% and 3.04%, respectively. 相似文献
954.
A simple strategy was developed based on a new reactive function‐ and a salt‐containing new monomer, 4‐vinylbenzyl dimethyl 2‐(dimethylphosphino)ethyl phosphonium chloride (VDEPC), to obtain stable humidity‐sensitive membranes. The major ingredient of a humid membrane is crosslinked polyelectrolytes obtained from copolymers of VDEPC/2‐ethylhexyl acrylate (2‐EHA) = 1/0, 4/1, and 2/1. Isothermal humidity absorption experiments were performed for the estimation of humidity‐sensing materials. The crosslinked copolymers prepared from the reaction of VDEPC/2‐EHA = 4/1 with 1,4‐dichlorobutane showed an average impedance of 595, 39.1, and 3.9 KΩ at 30, 60, and 90% RH, respectively. Their hysteresis, temperature dependence, frequency dependence, and response time were measured. The reliability including water resistance and a long‐term stability were estimated for the application of the common humidity sensor. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1062–1070, 2003 相似文献
955.
Yanyan Dai Suk Gyu Lee 《International Journal of Control, Automation and Systems》2014,12(5):1077-1089
This paper deals with the problem of formation control for nonholonomic mobile robots under a cluttered environment. When the obstacles are not detected, the follower robot calculates its waypoint to track, based on the leader robot’s state. The proposed geometric obstacle avoidance control method (GOACM) guarantees that the robot avoids the static and dynamic obstacles using onboard sensors. Due to the difficulty for the robot to simultaneously get overall safe boundary of an obstacle in practice, a safe line, which is perpendicular to the obstacle surface, is used instead of the safe boundary. Since GOACM is executed to find a safe waypoint for the robot, GOACM can effectively cooperate with the formation control method. Moreover, the adaptive controllers guarantee that the trajectory and velocity tracking errors converge to zero with the consideration of the parametric uncertainties of both kinematic and dynamic models. Simulation and experiment results present that the robots effectively form and maintain formation avoiding the obstacles. 相似文献
956.
Vo Quang Nhat Gueesang Lee 《International Journal of Control, Automation and Systems》2014,12(1):195-201
Since the introduction of the sparse representation-based tracking method named ?1 tracker, there have been further studies into this tracking framework with promised results in challenging video sequences. However, in the situation of large illumination changes and shadow casting, the tracked object cannot be modeled efficiently by sparse representation templates. To overcome this problem, we propose a new illumination invariant tracker based on photometric normalization techniques and the sparse representation framework. With photometric normalization methods, we designed a new illumination invariant template presentation for tracking that eliminates the illumination influences, such as brightness variation and shadow casting. For a higher tracking accuracy, we introduced a strategy that adaptively selects the optimum template presentation at the update step of the tracking process. The experiments show that our approach outperforms the previous ?1 and some state-of-the-art algorithms in tracking sequences with severe illumination effects. 相似文献
957.
An Yong Lee Jongguk Yim Youngjin Choi 《International Journal of Control, Automation and Systems》2014,12(5):1102-1109
This paper presents a scaled Jacobian transpose based control method for robotic manipulators as a modification of a conventional Jacobian transpose based method. The proposed method has several advantages such as it shows faster convergence and better tracking performance than the conventional method, furthermore, it does not have any singularity problem similar to the conventional method. The scaled Jacobian transpose is obtained by collecting each pseudoinverse of the column vector of the Jacobian matrix. The proposed method performs a given task well under singular configurations while minimizing the task error. Finally, a few comparative studies with the conventional method are provided to show the effectiveness of the proposed method through simulations. 相似文献
958.
Hong-Gi Lee Jung Youn Lee Kyung-Duk Kim Hoon Kang 《International Journal of Control, Automation and Systems》2014,12(5):1124-1130
Unlike the continuous-time case, algebraic necessary and sufficient conditions for a single output discrete-time system to be state equivalent to a nonlinear observer canonical form have been found and are easier to verify for those who are not accustomed to differential geometry. The geometric conditions look very different from the algebraic conditions. In this paper, we show direct equivalence of the geometric conditions and the algebraic conditions in order to enhance the understanding of the geometric conditions. 相似文献
959.
Ashwin Kumar Vutha Benyamin Davaji Chung Hoon Lee Glenn M. Walker 《Microfluidics and nanofluidics》2014,17(5):871-878
We demonstrate the use of heat to count microscopic particles. A thermal particle detector (TPD) was fabricated by combining a 500-nm-thick silicon nitride membrane containing a thin-film resistive temperature detector with a silicone elastomer microchannel. Particles with diameters of 90 and 200 μm created relative temperature changes of 0.11 and ?0.44 K, respectively, as they flowed by the sensor. A first-order lumped thermal model was developed to predict the temperature changes. Multiple particles were counted in series to demonstrate the utility of the TPD as a particle counter. 相似文献
960.
Young-Ho Lee Shin-Guk Kim Tae-Yong Kuc Jong-Koo Park Sang-Hoon Ji Yong-Seon Moon Young-Jo Cho 《International Journal of Control, Automation and Systems》2014,12(2):390-398
A virtual target tracking approach is proposed for kinematic control of mobile robot. In the controller, linear and angular velocity inputs are generated by using the local data of robot position and orientation along with the estimated velocity of target object. Applying the proposed approach to a cooperative robot group with arbitrary number of multiple mobile robots, it is possible to create various robot formations for cooperative navigation and tracking of moving object. The developed controller is shown to be stable and convergent through theoretical proof and a series of experiments. 相似文献