全文获取类型
收费全文 | 22481篇 |
免费 | 2360篇 |
国内免费 | 1473篇 |
专业分类
电工技术 | 3981篇 |
综合类 | 2872篇 |
化学工业 | 1081篇 |
金属工艺 | 713篇 |
机械仪表 | 2295篇 |
建筑科学 | 653篇 |
矿业工程 | 548篇 |
能源动力 | 518篇 |
轻工业 | 447篇 |
水利工程 | 248篇 |
石油天然气 | 350篇 |
武器工业 | 286篇 |
无线电 | 2799篇 |
一般工业技术 | 1898篇 |
冶金工业 | 534篇 |
原子能技术 | 166篇 |
自动化技术 | 6925篇 |
出版年
2024年 | 38篇 |
2023年 | 257篇 |
2022年 | 314篇 |
2021年 | 482篇 |
2020年 | 644篇 |
2019年 | 615篇 |
2018年 | 605篇 |
2017年 | 782篇 |
2016年 | 849篇 |
2015年 | 853篇 |
2014年 | 1222篇 |
2013年 | 1344篇 |
2012年 | 1604篇 |
2011年 | 1737篇 |
2010年 | 1255篇 |
2009年 | 1285篇 |
2008年 | 1375篇 |
2007年 | 1646篇 |
2006年 | 1478篇 |
2005年 | 1314篇 |
2004年 | 1076篇 |
2003年 | 981篇 |
2002年 | 821篇 |
2001年 | 669篇 |
2000年 | 612篇 |
1999年 | 468篇 |
1998年 | 372篇 |
1997年 | 323篇 |
1996年 | 239篇 |
1995年 | 201篇 |
1994年 | 187篇 |
1993年 | 116篇 |
1992年 | 132篇 |
1991年 | 80篇 |
1990年 | 72篇 |
1989年 | 49篇 |
1988年 | 43篇 |
1987年 | 20篇 |
1986年 | 25篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 16篇 |
1981年 | 16篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1966年 | 6篇 |
1964年 | 13篇 |
1963年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Ya Gu Quanmin Zhu Hassan Nouri 《International Journal of Adaptive Control and Signal Processing》2022,36(1):138-154
This article presents a state-space model with time-delay to map the relationship between known input-output data for discrete systems. For the given input-output data, a model identification algorithm combining parameter estimation and state estimation is proposed in line with the causality constraints. Consequently, this article proposes a least squares parameter estimation algorithm, and analyzes its convergence for the studied systems to prove that the parameter estimation errors converge to zero under the persistent excitation conditions. In control system design, the U-model based control is introduced to provide a unilateral platform to improve the design efficiency and generality. A simulation portfolio from modeling to control is provided with computational experiments to validate the derived results. 相似文献
2.
Output feedback controller for polytopic systems exploiting the direct searching of the design space
This paper deals with the problem of designing a robust static output feedback controller for polytopic systems. The current research that tackled this problem is mainly based on LMI method, which is conservative by nature. In this paper, a novel approach is proposed, which considers the design space of the controller parameters and iteratively partitions the space to small simplexes. Then, by assessing the stability in each simplex, the solution space for design parameters is directly determined. It has been theoretically proved that, if there exists a feasible solution in the design space, the algorithm can find it. To validate the result of the proposed approach, comparative simulation examples are given to illustrate the performance of the design methodology as compared to those of previous approaches. 相似文献
3.
4.
5.
This paper investigates a renewable energy resource’s application to the Load–Frequency Control of interconnected power system. The Proportional-Integral (PI) controllers are replaced with Proportional-Integral Plus (PI+) controllers in a two area interconnected thermal power system without/with the fast acting energy storage devices and are designed based on Control Performance Standards (CPS) using conventional/Beta Wavelet Neural Network (BWNN) approaches. The energy storing devices Hydrogen generative Aqua Electroliser (HAE) with Fuel cell and Redox Flow Battery (RFB) are incorporated to the two area interconnected thermal power system to efficiently damp out the electromechanical oscillations in the power system because of their inherent efficient storage capacity in addition to the kinetic energy of the generator rotor, which can share the sudden changes in power requirements. The system was simulated and the frequency deviations in area 1 and area 2 and tie-line power deviations for 5% step- load disturbance in area 1 are obtained. The comparison of frequency deviations and tie-line power deviations of the two area interconnected thermal power system with HAE and RFB designed with BWNN controller reveals that the PI+ controller designed using BWNN approach is found to be superior than that of output response obtained using PI+ controller. Moreover the BWNN based PI+ controller exhibits a better transient and steady state response for the interconnected power system with Hydrogen generative Aqua Electroliser (AE) unit than that of the system with Redox Flow Battery (RFB) unit. 相似文献
6.
ARIMA is seldom used in supply chains in practice. There are several reasons, not the least of which is the small sample size of available data, which restricts the usage of the model. Keeping in mind this restriction, we discuss in this paper a state-space ARIMA model with a single source of error and show how it can be efficiently used in the supply-chain context, especially in cases when only two seasonal cycles of data are available. We propose a new order selection algorithm for the model and compare its performance with the conventional ARIMA on real data. We show that the proposed model performs well in terms of both accuracy and computational time in comparison with other ARIMA implementations, which makes it efficient in the supply-chain context. 相似文献
7.
AbstractModel order reduction is a common practice to reduce large order systems so that their simulation and control become easy. Nonlinearity aware trajectory piecewise linear is a variation of trajectory piecewise linearization technique of order reduction that is used to reduce nonlinear systems. With this scheme, the reduced approximation of the system is generated by weighted sum of the linearized and reduced sub-models obtained at certain linearization points on the system trajectory. This scheme uses dynamically inspired weight assignment that makes the approximation nonlinearity aware. Just as weight assignment, the process of linearization points selection is also important for generating faithful approximations. This article uses a global maximum error controller based linearization points selection scheme according to which a state is chosen as a linearization point if the error between a current reduced model and the full order nonlinear system reaches a maximum value. A combination that not only selects linearization points based on an error controller but also assigns dynamic inspired weights is shown in this article. The proposed scheme generates approximations with higher accuracies. This is demonstrated by applying the proposed method to some benchmark nonlinear circuits including RC ladder network and inverter chain circuit and comparing the results with the conventional schemes. 相似文献
8.
9.
Production planning and control (PPC) systems that employ aspects from both make-to-order (MTO) and make-to-stock (MTS) production control are known as hybrid MTS/MTO systems. While both MTO and MTS separately have been studied extensively, their combined use has received less attention. However, the literature on this topic is growing and this paper shows that the review performed in this paper is an important addition to the field. We categorise relevant literature according to a novel taxonomy and show that hybrid MTS/MTO production control can be used in different contexts. In addition, an overview of the modelling techniques and methods used in these papers is provided. Based on the reviewed literature, relevant research questions and directions for future research are identified. Finally, it is shown that hybrid MTS/MTO production control is prevalent in practice by discussing research with industrial applications. The paper contains an overview of research on hybrid MTS/MTO production control to be used as reference for researchers active in the field, and provides managerial insights and directions for future research on this topic. 相似文献
10.
图像纹理增强过程中容易丢失平滑区域纹理细节,而分数阶微分增强虽然能够非线性保留平滑区域纹理细节,但对频率分辨率敏感。针对这个问题,提出一种基于小波变换的分数阶微分纹理增强算法,应用于平扫计算机断层扫描(CT)图像的肝脏肿瘤区域的纹理增强。首先,通过小波变换将图像感兴趣区分解成多个子带分量;其次,基于分数阶微分定义构造一个带补偿参数的分数阶微分掩膜;最后,使用该掩膜与每个高频子带分量进行卷积并利用小波逆变换重组图像感兴趣区。实验结果表明,该方法在使用较大分数阶次显著增强肿瘤区域的高频轮廓信息的同时,有效地保留了低频平滑的纹理细节:增强后的肝细胞癌区域与原区域相比,信息熵平均增加36.56%,平均梯度平均增加321.56%,平均绝对差值平均为9.287;增强后的肝血管瘤区域与原区域相比,信息熵平均增加48.77%,平均梯度平均增加511.26%,平均绝对差值平均为14.097。 相似文献