全文获取类型
收费全文 | 1182篇 |
免费 | 67篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 19篇 |
化学工业 | 319篇 |
金属工艺 | 20篇 |
机械仪表 | 24篇 |
建筑科学 | 43篇 |
矿业工程 | 5篇 |
能源动力 | 56篇 |
轻工业 | 160篇 |
水利工程 | 11篇 |
石油天然气 | 2篇 |
无线电 | 78篇 |
一般工业技术 | 202篇 |
冶金工业 | 131篇 |
原子能技术 | 8篇 |
自动化技术 | 172篇 |
出版年
2023年 | 11篇 |
2022年 | 33篇 |
2021年 | 47篇 |
2020年 | 21篇 |
2019年 | 32篇 |
2018年 | 54篇 |
2017年 | 44篇 |
2016年 | 35篇 |
2015年 | 25篇 |
2014年 | 41篇 |
2013年 | 85篇 |
2012年 | 69篇 |
2011年 | 83篇 |
2010年 | 55篇 |
2009年 | 54篇 |
2008年 | 41篇 |
2007年 | 54篇 |
2006年 | 45篇 |
2005年 | 28篇 |
2004年 | 30篇 |
2003年 | 24篇 |
2002年 | 28篇 |
2001年 | 14篇 |
2000年 | 17篇 |
1999年 | 13篇 |
1998年 | 40篇 |
1997年 | 22篇 |
1996年 | 23篇 |
1995年 | 17篇 |
1994年 | 12篇 |
1993年 | 16篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 11篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有1250条查询结果,搜索用时 0 毫秒
21.
Yingda Cheng Irene M. Gamba Armando Majorana Chi-Wang Shu 《Computer Methods in Applied Mechanics and Engineering》2009,198(37-40):3130-3150
In this paper, we present results of a discontinuous Galerkin (DG) scheme applied to deterministic computations of the transients for the Boltzmann–Poisson system describing electron transport in semiconductor devices. The collisional term models optical-phonon interactions which become dominant under strong energetic conditions corresponding to nano-scale active regions under applied bias. The proposed numerical technique is a finite element method using discontinuous piecewise polynomials as basis functions on unstructured meshes. It is applied to simulate hot electron transport in bulk silicon, in a silicon n+–n–n+ diode and in a double gated 12 nm MOSFET. Additionally, the obtained results are compared to those of a high order WENO scheme simulation and DSMC (Discrete Simulation Monte Carlo) solvers. 相似文献
22.
The simulation of the wind action over the CAARC (Commonwealth Advisory Aeronautical Council) standard tall building model is performed in the present work. Aerodynamic and aeroelastic analyses are reproduced numerically in order to demonstrate the applicability of CFD techniques in the field of wind engineering. A major topic in this paper is referred to one of the first attempts to simulate the aeroelastic behavior of a tall building employing complex CFD techniques. Numerical results obtained in this work are compared with numerical and wind tunnel measurements and some important concluding remarks about the present simulation are also reported. 相似文献
23.
Yin Zhaoxia Abel Andrew Tang Jin Zhang Xinpeng Luo Bin 《Multimedia Tools and Applications》2017,76(3):3899-3920
Multimedia Tools and Applications - In recent years there has been significant interest in reversible data hiding, and also in particular, reversible data hiding in encrypted images (RDH-EI). This... 相似文献
24.
Armando Manuel Fernandes 《Pattern recognition》2011,44(2):488-489
We correct a fundamental formula from paper “A Robust Real-Time Ellipse Detector” by Zhang and Liu published in journal “Pattern Recognition” in 2005. 相似文献
25.
Lounis Kessal Nicolas Abel Si Mahmoud Karabernou Didier Demigny 《Journal of Real-Time Image Processing》2008,3(3):131-147
Technology evolution makes possible the integration of heterogeneous components as programmable elements (processors), hardware
dedicated blocks, hierarchical memories and buses. Furthermore, an optimized reconfigurable logic core embedded within a System-on-Chip
will associate the performances of dedicated architecture and the flexibility of programmable ones. In order to increase performances,
some of the applications are carried out in hardware, using dynamically reconfigurable logic, rather than software, using
programmable elements. This approach offers a suitable hardware support to design malleable systems able to adapt themselves
to a specific application. This article makes a synthesis of the Ardoise project. The first objective of Ardoise project was
to design and to produce a dynamically reconfigurable platform based on commercial FPGAs. The concept of dynamically reconfigurable
architecture depends partially on new design methodologies elaboration as well as on the programming environment. The platform
architecture was designed to be suitable for real-time image processing. The article outlines mainly the Ardoise tools aspect:
development environment and real-time management of the hardware tasks. The proposed methodology is based on a dynamic management
of tasks according to an application scenario written using C++ language.
相似文献
Lounis KessalEmail: |
26.
Kian-Lee Tan Beng Chin Ooi Abel D.J. 《Knowledge and Data Engineering, IEEE Transactions on》2000,12(6):920-937
In a distributed spatial database system, a user may issue a query that relates two spatial relations not stored at the same site. Because of the sheer volume and complexity of spatial data, spatial joins between two spatial relations at different sites are expensive in terms of computational and transmission costs. In this paper, we address the problems of processing spatial joins in a distributed environment. We propose a semijoin-like operator, called the spatial semijoin, to prune away objects that do not contribute to the join result. This operator also reduces both the transmission and local processing costs for a later join operation. However, the cost of the elimination process must be taken into account, and we consider approaches to minimize these overheads. We also study and compare two families of distributed join algorithms that are based on the spatial semijoin operator. The first is based on multi-dimensional approximations obtained from an index such as the R-tree, and the second is based on single-dimensional approximations obtained from object mapping. We have conducted experiments on real data sets and report the results in this paper 相似文献
27.
Paulo Leit?o J. Marco Mendes Axel Bepperling Daniel Cachapa Armando W. Colombo Francisco Restivo 《Journal of Intelligent Manufacturing》2012,23(6):2551-2563
Engineering frameworks are currently required to support the easy, low-cost, modular and integrated development of manufacturing systems addressing the emergent requirements of re-configurability, responsiveness and robustness. This paper discusses the integration of 2D/3D digital software tools with Petri net based service-oriented frameworks to allow the design, configuration, analysis, validation, simulation, monitoring and control of manufacturing systems in a virtual environment and its posterior smooth migration into the real ??physical?? environment. An experimental case study was implemented to validate the proposed concepts, using the Continuum platform to design, compose, analyze, validate and simulate the Petri nets based service-oriented manufacturing control system, and the Delmia AutomationTM software suite to support the rapid prototyping and the easy simulation of the designed control solution. The experimental results prove several aspects of the proposed approach, notably the smooth migration between the design and the operation phases, one of the main objectives of the work. 相似文献
28.
Bernardete Ribeiro Catarina Silva Ning Chen Armando Vieira João Carvalho das Neves 《Expert systems with applications》2012,39(11):10140-10152
Default risk models have lately raised a great interest due to the recent world economic crisis. In spite of many advanced techniques that have extensively been proposed, no comprehensive method incorporating a holistic perspective has hitherto been considered. Thus, the existing models for bankruptcy prediction lack the whole coverage of contextual knowledge which may prevent the decision makers such as investors and financial analysts to take the right decisions. Recently, SVM+ provides a formal way to incorporate additional information (not only training data) onto the learning models improving generalization. In financial settings examples of such non-financial (though relevant) information are marketing reports, competitors landscape, economic environment, customers screening, industry trends, etc. By exploiting additional information able to improve classical inductive learning we propose a prediction model where data is naturally separated into several structured groups clustered by the size and annual turnover of the firms. Experimental results in the setting of a heterogeneous data set of French companies demonstrated that the proposed default risk model showed better predictability performance than the baseline SVM and multi-task learning with SVM. 相似文献
29.
A class of mixed finite elements based on the Hu-Washizu functional is introduced as a strategy to reduce the spurious stress phenomena encountered with standard or displacement-based formulations for geometrically exact membranes. Selected examples compare the performance of this class of elements with that of the standard formulation and demonstrate that reduction of spurious stresses is obtained and that the stresses are more accurate than those optimally sampled in the standard formulation. 相似文献
30.
The scope of the article is to describe the automated production of a thixoformed steel part. The production plant was set up within a prototype initiative at the Institute of Metal Forming in cooperation with the Institute of Automatic Control of RWTH Aachen University and industrial partners. Preliminary experiments showed that the quality of the formed parts varied to a great extent due to changing production conditions since the handling of the billet was carried out manually. To eliminate the possible disturbances introduced by the manual handling of the billet, an automation concept has been elaborated in order to guarantee a defined production environment. An industrial robot (KUKA) fulfils the handling tasks like the feeding of the induction coil with the feedstock material and the placing of the heated billet into the hydraulic press. The removal of the formed part from the press is realised by a simple mechanical device in order to be able to use only one gripper. The design of the gripper ensures a minimal heat loss during handling. The induction coil, the gripper system and the cavity are flooded with inert gas in order to prevent scaling. The sequence control for the production of a part is realised on the controller of the robot which provides sufficient PLC functionality and can be easily equipped with the required I/O components to trigger the different automation components. 相似文献