全文获取类型
收费全文 | 2670篇 |
免费 | 337篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 30篇 |
综合类 | 4篇 |
化学工业 | 656篇 |
金属工艺 | 114篇 |
机械仪表 | 162篇 |
建筑科学 | 55篇 |
能源动力 | 133篇 |
轻工业 | 177篇 |
水利工程 | 8篇 |
石油天然气 | 2篇 |
无线电 | 544篇 |
一般工业技术 | 719篇 |
冶金工业 | 98篇 |
原子能技术 | 20篇 |
自动化技术 | 291篇 |
出版年
2024年 | 4篇 |
2023年 | 27篇 |
2022年 | 33篇 |
2021年 | 78篇 |
2020年 | 71篇 |
2019年 | 83篇 |
2018年 | 114篇 |
2017年 | 134篇 |
2016年 | 124篇 |
2015年 | 129篇 |
2014年 | 162篇 |
2013年 | 204篇 |
2012年 | 197篇 |
2011年 | 276篇 |
2010年 | 205篇 |
2009年 | 198篇 |
2008年 | 158篇 |
2007年 | 116篇 |
2006年 | 112篇 |
2005年 | 72篇 |
2004年 | 63篇 |
2003年 | 72篇 |
2002年 | 81篇 |
2001年 | 39篇 |
2000年 | 44篇 |
1999年 | 28篇 |
1998年 | 42篇 |
1997年 | 29篇 |
1996年 | 20篇 |
1995年 | 18篇 |
1994年 | 9篇 |
1993年 | 16篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3013条查询结果,搜索用时 218 毫秒
81.
User authentication is one of the fundamental procedures to ensure secure communications over an insecure public network channel. Especially, due to tamper-resistance and convenience in managing a password file, various user authentication schemes using smart cards have been proposed. A smart card however far from ubiquitous because of the high cost of a smart card and the infrastructure requirements. In this paper, we study secure user authentication using only a common storage device such as a universal serial bus (USB) memory, instead of using smart cards. We first show that the existing schemes using smart cards cannot be immediately converted into schemes using a common storage device. We then propose a practical and secure user authentication scheme, capable of supporting the use of the common storage device, which retains all the advantages of schemes using smart cards. 相似文献
82.
Radio frequency Identification (RFID) systems are used to identify remote objects equipped with RFID tags by wireless scanning without manual intervention. Recently, EPCglobal proposed the Electronic Product Code (EPC) that is a coding scheme considered to be a possible successor to bar-code with added functionalities. In RFID-based applications where RFID tags are used to identify and track tagged objects, an RFID tag emits its EPC in plaintext. This makes the tag inevitably vulnerable to cloning attacks as well as information leakage and password disclosure. In this paper, we propose a novel anti-cloning method in accordance with the EPCglobal Class-1 Generation-2 (C1G2) standard. Our method only uses functions that can be supported by the standard and abides by the communication flow of the standard. The method is also secure against threats such as information leakage and password disclosure. 相似文献
83.
84.
This paper presents a decentralised sampled-data control technique for a class of large-scale systems, which are considered to consist of linear subsystems and nonlinear interconnections. The decentralised sampled-data controller design problem is established using a closed-loop subsystem. Based on the controller design problem, the stability condition is derived for a closed-loop large-scale system, and the maximum interconnection bound is guaranteed to satisfy the stability condition. Also, its sufficient condition is formulated in terms of linear matrix inequalities. Finally, the effectiveness of the proposed technique is verified by using an example of the multi-machine power system. 相似文献
85.
Digital image processing systems are complex, being usually composed of different computer vision libraries. Algorithm implementations cannot be directly used in conjunction with algorithms developed using other computer vision libraries. This paper formulates a software solution by proposing a processor with the capability of handling different types of image processing algorithms, which allow the end users to install new image processing algorithms from any library. This approach has other functionalities like capability to process one or more images, manage multiple processing jobs simultaneously and maintain the manner in which an image was processed for later use. It is a computational efficient and promising technique to handle variety of image processing algorithms. To promote the reusability and adaptation of the package for new types of analysis, a feature of sustainability is established. The framework is integrated and tested on a medical imaging application, and the software is made freely available for the reader. Future work involves introducing the capability to connect to another instance of processing service with better performance. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
86.
Ho Jun Kim Jin Bae Park Young Hoon Joo 《International Journal of Control, Automation and Systems》2017,15(2):603-610
This paper presents a fuzzy filter design method for nonlinear sampled-data systems using an intelligent digital redesign (IDR) technique. Based on a Takagi–Sugeno (T–S) fuzzy model, discretized closed-loop systems with pre-designed analog fuzzy and digital fuzzy filters are presented. An IDR problem is given to guarantee both state-matching condition and asymptotic stability. Sufficient conditions for solving the IDR problem are proposed and are derived in terms of linear matrix inequalities (LMIs). Finally, a simulation example is given to show the effectiveness of the proposed method. 相似文献
87.
This paper provides simple and effective linear matrix inequality (LMI) characterizations for the stability and stabilization conditions of discrete-time Takagi–Sugeno (T–S) fuzzy systems. To do this, more general classes of non-parallel distributed compensation (non-PDC) control laws and non-quadratic Lyapunov functions are presented. Unlike the conventional non-quadratic approaches using only current-time normalized fuzzy weighting functions, we consider not only the current-time fuzzy weighting functions but also the l-step-past (l?0) and one-step-ahead ones when constructing the control laws and Lyapunov functions. Consequently, by introducing additional decision variables, it can be shown that the proposed conditions include the existing ones found in the literature as particular cases. Examples are given to demonstrate the effectiveness of the approaches. 相似文献
88.
It has already been recognized that looking for a positive definite Lyapunov function such that a high-order linear differential inequality with respect to the Lyapunov function holds along the trajectories of a nonlinear system can be utilized to assess asymptotic stability when the standard Lyapunov approach examining only the first derivative fails. In this context, the main purpose of this paper is, on one hand, to theoretically unveil deeper connections among existing stability conditions especially for linear time-invariant (LTI) systems, and from the other hand to examine the effect of the higher-order time-derivatives approach on the stability results for uncertain polytopic LTI systems in terms of conservativeness. To this end, new linear matrix inequality (LMI) stability conditions are derived by generalizing the concept mentioned above, and through the development, relations among some existing stability conditions are revealed. Examples illustrate the improvement over the quadratic approach. 相似文献
89.
The election problem in asynchronous distributed systems with bounded faulty processes 总被引:1,自引:1,他引:0
Sung Hoon Park 《The Journal of supercomputing》2007,41(1):89-104
Determining the “weakest” failure detectors is a central topic in solving many agreement problems such as Consensus, Non-Blocking
Atomic Commit and Election in asynchronous distributed systems. So far, this has been studied extensively for several such
fundamental problems. It is stated that Perfect Failure Detector P is the weakest failure detector to solve the Election problem with any number of faulty processes. In this paper, we introduce
Modal failure detector M and show that to solve Election, M is the weakest failure detector to solve election when the number of faulty processes is less than ⌈n/2⌉. We also show that it is strictly weaker than P.
相似文献
Sung Hoon ParkEmail: |
90.
A series of catalysts, NiSO4/TiO2-ZrO2, for ethylene dimerization was prepared by the impregnation method using an aqueous solution of nickel sulfate. For NiSO4/TiO2 -ZrO2 sample, no diffraction line of nickel sulfate was observed up to 30 wt%, indicating good dispersion of nickel sulfate on the surface of TiO2-ZrO2. The addition of nickel sulfate to TiO2-ZrO2 shifted the phase transition of TiZrO4 from amorphous to orthorhombic to a higher temperature because of the interaction between nickel sulfate and TiO2-ZrO2. The number of acid sites of NiSO4/TiO2-ZrO2 increased in proportion to the nickel sulfate content up to 20 wt% of NiSO4. Nickel sulfate supported on TiO2-ZrO2 was found to be very active even at room temperature, giving a maximum in both activity and acidity when the catalyst containing 20% NiSO4 was calcined and evacuated at 500°C The asymmetric stretching frequency of the S=O bonds for NiSO4/TiO2-ZrO2 samples was related to the acidic properties and catalytic activity. That is, the higher the frequency, the higher both the number of acid sites and the catalytic activity for ethylene dimerization. 相似文献