全文获取类型
收费全文 | 5767篇 |
免费 | 363篇 |
国内免费 | 33篇 |
专业分类
电工技术 | 125篇 |
综合类 | 5篇 |
化学工业 | 1616篇 |
金属工艺 | 180篇 |
机械仪表 | 178篇 |
建筑科学 | 220篇 |
矿业工程 | 12篇 |
能源动力 | 301篇 |
轻工业 | 548篇 |
水利工程 | 44篇 |
石油天然气 | 94篇 |
武器工业 | 1篇 |
无线电 | 547篇 |
一般工业技术 | 1053篇 |
冶金工业 | 395篇 |
原子能技术 | 34篇 |
自动化技术 | 810篇 |
出版年
2023年 | 63篇 |
2022年 | 158篇 |
2021年 | 192篇 |
2020年 | 156篇 |
2019年 | 224篇 |
2018年 | 309篇 |
2017年 | 221篇 |
2016年 | 248篇 |
2015年 | 200篇 |
2014年 | 238篇 |
2013年 | 497篇 |
2012年 | 289篇 |
2011年 | 370篇 |
2010年 | 303篇 |
2009年 | 293篇 |
2008年 | 270篇 |
2007年 | 201篇 |
2006年 | 215篇 |
2005年 | 139篇 |
2004年 | 137篇 |
2003年 | 168篇 |
2002年 | 125篇 |
2001年 | 101篇 |
2000年 | 107篇 |
1999年 | 85篇 |
1998年 | 115篇 |
1997年 | 70篇 |
1996年 | 56篇 |
1995年 | 46篇 |
1994年 | 39篇 |
1993年 | 34篇 |
1992年 | 22篇 |
1991年 | 29篇 |
1990年 | 21篇 |
1989年 | 23篇 |
1988年 | 25篇 |
1987年 | 42篇 |
1986年 | 24篇 |
1985年 | 27篇 |
1984年 | 24篇 |
1983年 | 25篇 |
1982年 | 18篇 |
1981年 | 19篇 |
1980年 | 24篇 |
1979年 | 14篇 |
1978年 | 20篇 |
1977年 | 22篇 |
1976年 | 26篇 |
1975年 | 22篇 |
1973年 | 18篇 |
排序方式: 共有6163条查询结果,搜索用时 0 毫秒
71.
Uniprocessor schedulability theory made great strides, in part, due to the simplicity of composing the delay of a job from
the execution times of higher-priority jobs that preempt it. In this paper, we bound the end-to-end delay of a job in a multistage
pipeline as a function of job execution times on different stages under preemptive as well as non-preemptive scheduling. We
show that the end-to-end delay is bounded by that of a single virtual “bottleneck” stage plus a small additive component. This contribution effectively transforms the pipeline into a
single stage system. The wealth of schedulability analysis techniques derived for uniprocessors can then be applied to decide
the schedulability of the pipeline. The transformation does not require imposing artificial per-stage deadlines, but rather
models the pipeline as a whole and uses the end-to-end deadlines directly in the single-stage analysis. It also does not make
assumptions on job arrival patterns or periodicity and thus can be applied to periodic and aperiodic tasks alike. We show
through simulations that this approach outperforms previous pipeline schedulability tests except for very short pipelines
or when deadlines are sufficiently large. The reason lies in the way we account for execution overlap among stages. We discuss
how previous approaches account for overlap and point out interesting differences that lead to different performance advantages
in different cases. Further, we also show that in certain cases non-preemptive scheduling can result in higher system utilization
than preemptive scheduling in pipelined systems. We hope that the pipeline delay composition rule, derived in this paper,
may be a step towards a general schedulability analysis foundation for large distributed systems.
相似文献
Tarek AbdelzaherEmail: |
72.
Correia A. Abbas-Turki A. Bouyekhf R. El Moudni A. 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》2009,39(4):770-781
This paper proposes a model for invariant resource sharing problems in dioid algebra. A strong motivation for investigating the issue is the absence of a general systematic technique which can be used to tackle these problems. (min, +) constraints have been developed to handle resource sharing in Discrete-Event Dynamic Systems. In particular, the part that can be modeled by a Timed Event Graph induce (min, +)-linear equations which are constrained by the resource availability. The proposed algebraic model has been proved to describe the actual behavior of the systems dealt with. This paper will show two examples of systems that are modeled and controlled by means of this approach. 相似文献
73.
Zerrik El Hassan Ghafrani Fatima 《International Journal of Control, Automation and Systems》2009,7(2):297-304
The aim of this paper is to deal with an output controllability problem. It consists in driving the state of a distributed
parabolic system toward a state between two prescribed functions on a boundary subregion of the system evolution domain with
minimum energy control. Two necessary conditions are derived. The first one is formulated in terms of subdifferential associated
with a minimized functional. The second one is formulated as a system of equations for arguments of the Lagrange systems.
Numerical illustrations show the efficiency of the second approach and lead to some conjectures.
Recommended by Editorial Board member Fumitoshi Matsuno under the direction of Editor Jae Weon Choi.
Zerrik El Hassan is a Professor at the university Moulay Ismail of Meknes in Morocco. He was an Assistant Professor in the faculty of sciences
of Meknes and researcher at the university of Perpignan (France). He got his doctorat d etat in system regional analysis (1993)
at the University Mohammed V of Rabat, Morocco. Professor Zerrik wrote many papers and books in the area of systems analysis
and control. Now he is the Head of the research team MACS (Modeling Analysis and Control of Systems) at the university Moulay
Ismail of Meknes in Morocco.
Ghafrani Fatima is a Researcher at team MACS at the University Moulay Ismail of Meknes in Morocco. She wrote many papers in the area of systems
analysis and control. 相似文献
74.
We study the problem of stabilizing a distributed linear system on a subregion of its geometrical domain. We are concerned with two methods: the first approach enables us to characterize a stabilizing control via the steady state Riccati equation, and the second one is based on decomposing the state space into two suitable subspaces and studying the projections of the initial system onto such subspaces. The obtained results are performed through various examples. 相似文献
75.
B. A. Mansour S. E. Demian H. Shaban F. El Akkad 《Journal of Materials Science: Materials in Electronics》1994,5(1):38-40
The room temperature photoelectric response of undoped and lithium-doped Zn1–xMgxTe (0 x 0.50) alloys has been measured in the wavelength range 0.50 3.0 m. The response curve for undoped samples is characterized by a single peak in the band edge region. The peak shifts with composition in accordance with the expected shift in the energy band gap. Lithium-doped samples show an additional peak centred at 1.04 eV for all compositions. This peak is attributed to photo-generated holes in the split-off band created as the result of electronic transitions to shallow acceptor impurities. 相似文献
76.
In many distributed databases locality of reference is crucial to achieve acceptable performance. However, the purpose of data distribution is to spread the data among several remote sites. One way to solve this contradiction is to use partitioned data techniques. Instead of accessing the entire data, a site works on a fraction that is made locally available, thereby increasing the site's autonomy. We present a theory of partitioned data that formalizes the concept and establishes the basis to develop a correctness criterion and a concurrency control protocol for partitioned databases. Set-serializability is proposed as a correctness criterion and we suggest an implementation that integrates partitioned and non-partitioned data. To complete this study, the policies required in a real implementation are also analyzed.
Recommended by: Hector Garcia-Molina 相似文献
77.
Wakrim Layla El Yassini Abdessalam Khabba Asma Ibnyaich Saida Zeroual Abdelouhab Hassani Moha M’Rabet 《Wireless Personal Communications》2022,126(2):1145-1175
Wireless Personal Communications - Due to the development and growth of Internet platforms and web services as communication resources, the competition for the network and its limited resources is... 相似文献
78.
79.
80.