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111.
Aziz Rachid Hassan El Fadil Fouad Giri Abdellah Lassioui 《Asian journal of control》2020,22(5):1848-1859
In this work, we consider the problem of controlling a single‐phase on‐board battery electric vehicle (BEV) charger with vehicle‐to‐grid (V2G) technology. The BEV charger consists of a bidirectional ac‐dc power converter connected to the single‐phase power grid, followed by a bidirectional dc‐dc power converter interfacing an EV battery pack. The main control objectives are fourfold: (i) Unitary Power Factor (UPF) in grid‐side; (ii) tight dc‐bus voltage regulation; (iii) safety battery charge and battery discharge during the grid‐to‐vehicle (G2V) mode and V2G mode, respectively; and (iv) asymptotic stability of the closed loop system. After an accurate system modelling, a nonlinear controller is designed using a backstepping design technique. The point is that the battery inner voltage is not accessible to measurement. Therefore, a nonlinear observer is invoked in order to estimate all non‐measured variables making the solution cheaper and noiseless. It is shown using a formal analysis and numerical simulations, that the proposed output feedback controller (combining a nonlinear controller and a nonlinear observer) meets all control objectives. 相似文献
112.
Rachid Chebbi 《Chemical Engineering Communications》2017,204(3):283-288
Thermal effects are considered assuming a volatile component evaporates from a binary liquid mixture in a very long tube. The work is an extension of the work of Chebbi and Selim (2006) (isothermal case) to include evaporative cooling. A similarity solution is provided for the gas–liquid interface temperature and the temperature profiles in the liquid and gas phases. The analysis accounts for the motion of the gas–liquid interface and shows evaporative cooling as expected. The magnitude of evaporative cooling is found significant when volatility of the volatile component is sufficiently high. The validity of the approximations used in the solution is addressed. 相似文献
113.
Abderahmane Elidrissi Ouassini Krim Samir Ouslimane Mohamed Berrabeh Rachid Touzani 《应用聚合物科学杂志》2007,105(3):1623-1631
Polyurethane elastomers (PU) have been synthesized from polytetramethylene glycol 2000 (PTMG 2000); 4, 4′‐diphenylmethane diisocyanate (MDI) and 1, 4‐butanediol (BD) as chain extender. This synthesis has been done in two steps known as prepolymer methods. The concentration of soft segments and hydrogen attachment in the matrices, have been studied. The results show that the glass transition of the soft segment Tg(s) do not take any changes with the concentration of the soft segment in the matrices. Although, the glass transition temperature of the hard segment Tg(H) increases when the concentration of the hard segment increases in the matrices. In general, the properties of the polyurethane elastomers depend on the extenders nature, the synthesis methods, phase segregation etc. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
114.
115.
Rachid Chebbi 《Chemical engineering science》2005,60(23):6806-6813
Unidirectional gravity-inertial spreading of oil on calm water is investigated. In this stage of spreading, gravity force is balanced by inertia force as the main resisting force. The use of Fannelop and Waldman boundary condition, based on the analogy with the acoustic limit in gas dynamics, is extended and modified to account for the case of continuous discharge of oil on water. The results yield the spreading laws and the velocity and oil-thickness profiles. The oil spill spreading results are compared with the approximate method based on the dynamics of spreading of constant-volume spill, showing that the approximate method is conservative in a certain range. 相似文献
116.
Arezki Hammache Mohand Boughanem Rachid Ahmed-Ouamer 《Knowledge and Information Systems》2014,39(2):329-349
Most existing Information Retrieval model including probabilistic and vector space models are based on the term independence hypothesis. To go beyond this assumption and thereby capture the semantics of document and query more accurately, several works have incorporated phrases or other syntactic information in IR, such attempts have shown slight benefit, at best. Particularly in language modeling approaches this extension is achieved through the use of the bigram or n-gram models. However, in these models all bigrams/n-grams are considered and weighted uniformly. In this paper we introduce a new approach to select and weight relevant n-grams associated with a document. Experimental results on three TREC test collections showed an improvement over three strongest state-of-the-art model baselines, which are the original unigram language model, the Markov Random Field model, and the positional language model. 相似文献
117.
Carole Delporte-Gallet Hugues Fauconnier Rachid Guerraoui Andreas Tielmann 《Distributed Computing》2011,24(3-4):137-147
At the heart of distributed computing lies the fundamental result that the level of agreement that can be obtained in an asynchronous shared memory model where t processes can crash is exactly t?+?1. In other words, an adversary that can crash any subset of size at most t can prevent the processes from agreeing on t values. But what about all the other ${2^{2^n - 1} - (n+1)}$ adversaries that are not uniform in this sense and might crash certain combination of processes and not others? This paper presents a precise way to classify all adversaries. We introduce the notion of disagreement power: the biggest integer k for which the adversary can prevent processes from agreeing on k values. We show how to compute the disagreement power of an adversary and derive n equivalence classes of adversaries. 相似文献
118.
Mohamed A. Ameedeen Behzad Bordbar Rachid Anane 《Journal of Computer and System Sciences》2011,77(2):332-347
Among the factors that contribute to the inherent complexity of the software development process is the gap between the design and the formal analysis domains. Software design is often considered a human oriented task while the analysis phase draws on formal representation and mathematical foundations. An example of this dichotomy is the use of UML for the software design phase and Petri Nets for the analysis; a separation of concerns that leads to the creation of heterogeneous models. Although UML is widely accepted as a language that can be used to model the structural and behavioural aspects of a system, its lack of mathematical foundations is seen as a serious impediment to rigorous analysis. Petri Nets on the other hand have a strong mathematical basis that are well suited for formal analysis; they lack however the appeal and the ease-of-use of UML. A pressing concern for software developers is how to bridge the gap between these domains and allow for model interoperability and the integration of different toolsets across them, and thus reduce the complexity of the software development process. The aim of this paper is to present a Model Driven Development (MDD) model transformation which supports a seamless transition between UML and Petri Nets. This is achieved by model interoperability from UML Sequence Diagrams to Petri Nets and supported by tool integration. The model transformation framework allows a software system to be designed in terms of UML Sequence Diagrams and subjected to formal analysis by taking advantage of the strong mathematical framework of Petri Nets. The behaviour of a Personal Area Network will be used to illustrate the proposed approach and to highlight model interoperability and tool integration through the design, the transformation and the analysis phases. 相似文献
119.
In this paper, n-channel MOSFET’s with oxides 1.2, 1.5 and 1.8 nm thick are studied. In such devices the trap assisted tunnelling (TAT) current required to fit the gate current vs. gate voltage, Ig(Vg), characteristics is thought to flow through Si–SiO2 interface traps. After stress, it becomes a stress induced leakage current (SILC) which should allow to obtain interface trap density variations with stress. The TAT mechanism is discussed. Then, the Si–SiO2 interface trap densities extracted using the SILC and charge pumping (CP) are compared. Much larger trap creation rates are viewed by the SILC with regard to CP, questioning the occurrence of the SILC through interface traps. To answer this question the interaction between SILC and CP measurements is investigated. 相似文献
120.
Ilham Elazhary Boutouil Aziz Ben El Ayouchia Hicham Laamari Mouly Rachid El Haddad Mohammadine Anane Hafid Salah-Eddine Stiriba 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(1):166-178
Protection of Metals and Physical Chemistry of Surfaces - The corrosion inhibitory effect of (1-benzyl-1H-1,2,3-triazol-4-yl) methanol (BTM) for mild steel in 1 M HCl at (298–328 K) was... 相似文献