全文获取类型
收费全文 | 32176篇 |
免费 | 5339篇 |
国内免费 | 4222篇 |
学科分类
工业技术 | 41737篇 |
出版年
2024年 | 349篇 |
2023年 | 832篇 |
2022年 | 1188篇 |
2021年 | 1365篇 |
2020年 | 1531篇 |
2019年 | 1292篇 |
2018年 | 1190篇 |
2017年 | 1420篇 |
2016年 | 1478篇 |
2015年 | 1678篇 |
2014年 | 2471篇 |
2013年 | 2360篇 |
2012年 | 2615篇 |
2011年 | 2724篇 |
2010年 | 2140篇 |
2009年 | 2094篇 |
2008年 | 2085篇 |
2007年 | 2166篇 |
2006年 | 2009篇 |
2005年 | 1637篇 |
2004年 | 1352篇 |
2003年 | 1134篇 |
2002年 | 864篇 |
2001年 | 752篇 |
2000年 | 632篇 |
1999年 | 442篇 |
1998年 | 365篇 |
1997年 | 294篇 |
1996年 | 259篇 |
1995年 | 210篇 |
1994年 | 158篇 |
1993年 | 139篇 |
1992年 | 124篇 |
1991年 | 81篇 |
1990年 | 77篇 |
1989年 | 57篇 |
1988年 | 38篇 |
1987年 | 18篇 |
1986年 | 13篇 |
1985年 | 6篇 |
1984年 | 23篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1962年 | 3篇 |
1960年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
128kb/s电视电话系统中数码率缓存器的控制策略研究 总被引:2,自引:0,他引:2
本文探讨了电视电话/会议电视的H,261建议中低码率时(p=2)数码率缓存器的控制问题,提出一种既有宏观预分配又有微观分割的控制策略(简称GALS),并用测试图像序列进行了计算机模拟。将本文方法与RM8中有关策略作了比较,实验结果表明图像的主观质量有所改善。 相似文献
32.
The paper addresses the design of two-level power system stabilizers using an optimal reduced order model whose state variables are torque angles and speeds. The reduced order model retains their physical meaning and is used to design a two-level linear feedback controller that takes into account the realities and constraints of electrical power systems. The two-level control strategy is used, and a global control signal is generated from the output variables to minimize the effect of interactions. The effectiveness of this controller is evaluated and a multimachine system is given as an example to illustrate the advantages of the proposed method. Responses of the system with a two-level scheme and an optimal reduced order scheme are included for comparative analysis. 相似文献
33.
从中国石化股份有限公司浙江温岭石油分公司所面临的市场态势和企业的经营状况出发,考虑企业的长足发展,阐述了实施顾客满意(CS)战略的紧迫性,指出必须实施CS战略,必须要在组织落实、宣传发动、具体措施及奖惩分明的激励机制等各方面采取得力措施。 相似文献
34.
S. Akhtar D. S. Bernstein 《International Journal of Adaptive Control and Signal Processing》2005,19(10):745-767
Discrete‐time model reference adaptive control (MRAC) is considered with both least squares and projection algorithm parameter identification. For both cases complete Lyapunov proofs are given for stability and convergence. The results extend the approach of Johansson (Int. J. Control 1989; 50 (3):859–869) to include Lyapunov stability for MRAC when the normalized projection algorithm is used for parameter identification. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
35.
36.
Yurak Son Takuya Kamano Takashi Yasuno Takayuki Suzuki Hironobu Harada 《Electrical Engineering in Japan》2006,155(1):35-43
This paper describes the generation of adaptive gait patterns using new Central Pattern Generators (CPGs) including motor dynamic models for a quadruped robot under various environments. The CPGs act as the flexible oscillators of the joints and adjust joint angles to required values. The CPGs are interconnected with each other and sets of their coupling parameters are adjusted by a genetic algorithm so that the quadruped robot can realize stable and adequate gait patterns. Generation of gait patterns results in the formation of the CPG networks suitable for the formation of not only a straight walking pattern but also of rotating gait patterns. Experimental results demonstrate that the proposed CPG networks are effective for the automatic adjustment of the adaptive gait patterns for the tested quadruped robot under various environments. Furthermore, the target tracking control based on image processing is achieved by combining the general gait patterns. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(1): 35–43, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20225 相似文献
37.
Minyue Fu 《International Journal of Adaptive Control and Signal Processing》2006,20(5):197-211
The switching adaptive control method has been used for quite a few years to solve the adaptive stabilization and model reference adaptive control problems. However, a serious problem with the switching control method is that the number of ‘candidate’ controllers can potentially be very large, especially for multi‐input–multi‐output systems. In this paper, we consider a class of minimum‐phase multi‐input–multi‐output plants with some mild compactness assumptions. Given any polynomial reference input, we provide a switching control law which guarantees exponentially stability of the closed‐loop system with exponential tracking performance. The main contribution of the paper is that we give the minimum number of candidate controllers required for switching. In particular, the number is equal to 2 for single‐input–single‐output plants (one for each sign of the high‐frequency gain), and is equal to 2m for m‐input–m‐output plants. That is, the number is independent of the degree and the relative degree of the plant. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
38.
The notions of dynamical synchronization and adaptive dynamical synchronization problems are introduced. The algorithm solving adaptive synchronization problem for a subclass of Lurie systems with exciting input is proposed. The performance and potentialities of proposed solutions are demonstrated by two examples related to formation control and self‐organization of swarm systems. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
39.
An effective system control method is presented for applying a three‐phase current‐source PWM converter with a deadbeat controller to active power filters (APFs). In the shunt‐type configuration, the APF is controlled such that the current drawn by the APF from the utility is equal to the current harmonics and reactive current required for the load. To attain the time‐optimal response of the APF supply current, a two‐dimensional deadbeat control scheme is applied to APF current control. Furthermore, in order to cancel both the delay in the two‐dimensional deadbeat control scheme and the delay in DSP control strategy, an Adaptive Line Enhancer (ALE) is introduced in order to predict the desired value three sampling periods ahead. ALE has another function of bringing robustness to the deadbeat control system. Due to the ALE, settling time is made short in a transient state. On the other hand, total harmonic distortion (THD) of source currents can be minimized compared to the case where ideal identification of the controlled system can be made. The experimental results obtained from the DSP‐based APF are also reported. The compensating ability of this APF is very high in accuracy and responsiveness although the modulation frequency is rather low. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(1): 50–61, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20014 相似文献
40.
风险评估在加氢装置的应用 总被引:1,自引:0,他引:1
广州石化加氢(二)B装置采用基于风险的检测(RBI)技术,对装置的静设备与管道使用RBI软件RB—eye进行定量、定性分析以及失效概率、失效后果的评价,评估了装置的风险情况,制定了装景基于风险分析的检验策略。 相似文献