全文获取类型
收费全文 | 5324篇 |
免费 | 475篇 |
国内免费 | 55篇 |
专业分类
电工技术 | 60篇 |
综合类 | 22篇 |
化学工业 | 1240篇 |
金属工艺 | 75篇 |
机械仪表 | 262篇 |
建筑科学 | 99篇 |
矿业工程 | 8篇 |
能源动力 | 327篇 |
轻工业 | 708篇 |
水利工程 | 64篇 |
石油天然气 | 30篇 |
武器工业 | 1篇 |
无线电 | 688篇 |
一般工业技术 | 1205篇 |
冶金工业 | 83篇 |
原子能技术 | 52篇 |
自动化技术 | 930篇 |
出版年
2024年 | 36篇 |
2023年 | 205篇 |
2022年 | 477篇 |
2021年 | 747篇 |
2020年 | 454篇 |
2019年 | 511篇 |
2018年 | 465篇 |
2017年 | 386篇 |
2016年 | 387篇 |
2015年 | 236篇 |
2014年 | 284篇 |
2013年 | 383篇 |
2012年 | 225篇 |
2011年 | 284篇 |
2010年 | 160篇 |
2009年 | 136篇 |
2008年 | 89篇 |
2007年 | 90篇 |
2006年 | 33篇 |
2005年 | 24篇 |
2004年 | 34篇 |
2003年 | 25篇 |
2002年 | 17篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 14篇 |
1998年 | 17篇 |
1997年 | 9篇 |
1996年 | 12篇 |
1995年 | 16篇 |
1994年 | 7篇 |
1993年 | 12篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 1篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1961年 | 1篇 |
排序方式: 共有5854条查询结果,搜索用时 0 毫秒
171.
Microsystem Technologies - The objective of this research paper is to find the way to guide the worms in an electric field gradient for a specific time period. Research has been done to guide the... 相似文献
172.
173.
An abstract file system is defined here as a partial function from (absolute) paths to data. Such a file system determines
the set of valid paths. It allows the file system to be read and written at a valid path, and it allows the system to be modified
by the Unix operations for creation, removal, and moving of files and directories. We present abstract definitions (axioms)
for these operations. This specification is refined towards a pointer implementation. The challenge is to have a natural abstraction
function from the implementation to the specification, to define operations on the concrete store that behave exactly in the
same way as the corresponding functions on the abstract store, and to prove these facts. To mitigate the problems attached
to partial functions, we do this in two steps: first a refinement towards a pointer implementation with total functions, followed
by one that allows partial functions. These two refinements are proved correct by means of a number of invariants. Indeed,
the insights gained consist, on the one hand, of the invariants of the pointer implementation that are needed for the refinement
functions, and on the other hand of the precise enabling conditions of the operations on the different levels of abstraction.
Each of the three specification levels is enriched with a permission system for reading, writing, or executing, and the refinement
relations between these permission systems are explored. Files and directories are distinguished from the outset, but this
rarely affects our part of the specifications. All results have been verified with the proof assistant PVS, in particular,
that the invariants are preserved by the operations, and that, where the invariants hold, the operations commute with the
refinement functions. 相似文献
174.
175.
Scientometrics - In this study, we investigate the downloads behavior of readers for two well-known IEEE journals in the field of education, i.e., IEEE Transactions on Learning Technologies (TLT)... 相似文献
176.
Marinho P. Barcellos Rodolfo S. AntunesHisham H. Muhammad Ruthiano S. Munaretti 《Journal of Network and Computer Applications》2012,35(1):328-339
Simulation has been of paramount importance to the development of novel Internet protocols. Such an approach typically focuses on one of three domains: wireless and other link-layer technologies, routing protocols, and transport-layer mechanisms and protocols. Existing techniques can tackle well simulation at layers 2, 3 and 4 of the TCP/IP architecture, but are not flexible enough to appropriately deal with application-layer protocols. These require simulators that support the modeling of networks and components with different levels of abstraction. Simmcast is an object-oriented framework that focuses on the necessary flexibility for application-layer protocol research. A simulation can be developed by the simple extension of building blocks that closely resemble components of a real network such as hosts, links and routers. The internal complexity of these components, however, is hidden from the user, so he/she can focus on the implementation of the desired protocol characteristics. This paper describes the flexible simulation architecture proposed and instantiated through Simmcast, and draws lessons from our experience in designing, implementing and deploying it. We also present framework instances used to evaluate application-layer protocols, exemplifying how different kinds of simulations can be developed with Simmcast. 相似文献
177.
Khan Abdul Manan Yun Deok-won Zuhaib Khalil Muhammad Iqbal Junaid Yan Rui-Jun Khan Fatima Han Changsoo 《International Journal of Control, Automation and Systems》2017,15(2):802-814
International Journal of Control, Automation and Systems - In this paper, we have addressed two issues for upper limb assist exoskeleton. 1) Estimation of Desired Motion Intention (DMI); 2) Robust... 相似文献
178.
Muhammad Waseem Anwar Muhammad Rashid Farooque Azam Muhammad Kashif 《Design Automation for Embedded Systems》2017,21(1):1-36
Model Based System Engineering (MBSE) is a renowned approach in the context of embedded systems development. It is frequently used to deal with the structural and behavioral aspects of system design. However, the verification of system design is generally performed in isolation. It is particularly true in the context of assertion based verification. Consequently, there is a huge gap between system design and its verification that seriously effects the productivity and time-to market objectives. Therefore, in this research, we target to reduce this gap by exploiting the features of MBSE and SystemVerilog assertions (SVA’s). This article introduces a novel MBSE approach to model the design verification aspects of embedded systems, along with the system design (structural and behavioral aspects). We propose SystemVerilog in Object Constraint Language (SVOCL), an OCL temporal extension for SystemVerilog, to represent the design verification requirements by means of SVA’s. As a part of research, SVOCL transformation engine has been developed to generate SVA’s code in order to automate the design verification of embedded systems. The application of SVOCL has been validated through four case studies. 相似文献
179.
Weiming Xiang Jian Xiao Muhammad Naveed Iqbal 《International Journal of Adaptive Control and Signal Processing》2012,26(4):350-373
In this paper, several concepts of switching frequency are introduced to analyze the properties and performance of switched systems in infinite as well as finite‐time intervals. The observation is very motivating that different system properties and performances depend on different switching frequencies. Sufficient conditions ensuring asymptotic stability, ?2 gain performance, and state boundness are derived on the basis of the notions of switching frequency, respectively. Then, on the basis of the analysis results, the control synthesis problems are addressed. LMI‐based design algorithms are proposed to meet different control synthesis requirements. Numerical design examples are provided to demonstrate our results. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
180.
By the exponential increase in cellular communication area, the user demands and with their side problems also tend to increase. Several techniques such as cell splitting, frequency reuse, diversity and so on have already been applied to overcome these problems. In all these procedures, smart antenna is one of the best techniques used to boost capacities, enlarge bandwidth, raise the SIR ratios, minimize the effects of fading and improve MIMO communications. An ordinary antenna array which can turn up into a smart antenna array is due to the signal processing algorithms, which consists of angle of arrival (AOA) estimations and Beamforming. In this paper, I will discuss and analyse about the MUSIC algorithm for AOA estimation and least mean squares algorithm for Beamforming. 相似文献