全文获取类型
收费全文 | 1942篇 |
免费 | 104篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 14篇 |
综合类 | 1篇 |
化学工业 | 454篇 |
金属工艺 | 45篇 |
机械仪表 | 52篇 |
建筑科学 | 48篇 |
矿业工程 | 3篇 |
能源动力 | 84篇 |
轻工业 | 178篇 |
水利工程 | 11篇 |
石油天然气 | 20篇 |
无线电 | 181篇 |
一般工业技术 | 310篇 |
冶金工业 | 358篇 |
原子能技术 | 34篇 |
自动化技术 | 256篇 |
出版年
2024年 | 12篇 |
2023年 | 19篇 |
2022年 | 72篇 |
2021年 | 86篇 |
2020年 | 63篇 |
2019年 | 63篇 |
2018年 | 59篇 |
2017年 | 63篇 |
2016年 | 63篇 |
2015年 | 45篇 |
2014年 | 51篇 |
2013年 | 99篇 |
2012年 | 82篇 |
2011年 | 95篇 |
2010年 | 67篇 |
2009年 | 74篇 |
2008年 | 72篇 |
2007年 | 67篇 |
2006年 | 57篇 |
2005年 | 62篇 |
2004年 | 43篇 |
2003年 | 22篇 |
2002年 | 25篇 |
2001年 | 28篇 |
2000年 | 42篇 |
1999年 | 33篇 |
1998年 | 106篇 |
1997年 | 77篇 |
1996年 | 50篇 |
1995年 | 36篇 |
1994年 | 25篇 |
1993年 | 36篇 |
1992年 | 15篇 |
1991年 | 19篇 |
1990年 | 12篇 |
1988年 | 16篇 |
1987年 | 15篇 |
1986年 | 9篇 |
1985年 | 17篇 |
1983年 | 12篇 |
1982年 | 8篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 9篇 |
1978年 | 14篇 |
1977年 | 15篇 |
1976年 | 17篇 |
1973年 | 6篇 |
1972年 | 6篇 |
1969年 | 6篇 |
排序方式: 共有2049条查询结果,搜索用时 15 毫秒
31.
32.
Vibratory finishing is a widely-used manufacturing process in which a vibrating container filled with granular media becomes fluidized. The resulting bulk flow entrains workpieces and exposes their surfaces to the impacts resulting from the small-scale media vibrations. The bulk flow is responsible for entrainment and mixing, while the media vibration does work on the surfaces. The selection of machine vibration parameters is commonly based on experience due to the difficulty in predicting the fluidized bed behavior. In this work, a discrete element method was used to investigate how the bulk flow in an actual tub finisher filled with steel balls depends on the tub motion parameters through a parametric study. The underlying mechanisms that create and drive the bulk flow were identified by examining the relationships between the bulk flow rates and the wall forces. Finally, the connection between the wall motion and the wall forces was investigated. The tub frequency was the most effective control parameter and there was an optimal phase difference between the horizontal and vertical vibrations to maximize bulk flow. The relationship between the media packing at the walls and the tangential forces between the walls and the media explained the formation and speed of the bulk flow. Lastly, it was shown that the tangential wall forces, unlike the normal forces, cannot be obtained from the known wall motion alone since they also depend on the media velocities relative to the walls. 相似文献
33.
Vibratory finishing (VF) employs vibrationally-fluidized granular media to finish the surfaces of workpieces that are entrained in the flowing media. Its application has been based mostly on experience and trial-and-error due to the complexity of the granular material behavior. The present study used discrete element modeling (DEM) to investigate how the movement of a commercial two-dimensional tub finisher influenced the average particle speed of the media in a bed of smooth, steel, spherical particles, and thus the work that would be done on an entrained workpiece. The parameters governing the tub wall motion (frequency, in-plane amplitudes, and phases of vibration) and the coefficient of friction between the media and the wall were systematically varied in 71 three-dimensional DEM simulations. The average particle speed was affected mostly by the vertical amplitude of tub motion rather than by the frequency, and was mostly independent of other parameters of motion and of the wall friction. A strong relationship was found between the average particle speed and the work done by the wall per cycle of vibration. The normal force on the wall was also found to correlate strongly with the normal component of the wall velocity. Together, these relationships offer the potential to enable the analytical prediction of the average particle speed based on the motion parameters of the tub alone. The paper provides a set of practical guidelines for the control of the average particle speed in VF that are explained by the forces between the media and walls of the tub finisher. 相似文献
34.
35.
36.
Termination is one of the most interesting problems when dealing with context-sensitive rewrite systems. Although a good number of techniques for proving termination of context-sensitive rewriting (CSR) have been proposed so far, the adaptation to CSR of the dependency pair approach, one of the most powerful techniques for proving termination of rewriting, took some time and was possible only after introducing some new notions like collapsing dependency pairs, which are specific for CSR. In this paper, we develop the notion of context-sensitive dependency pair (CSDP) and show how to use CSDPs in proofs of termination of CSR. The implementation and practical use of the developed techniques yield a novel and powerful framework which improves the current state-of-the-art of methods for automatically proving termination of CSR. 相似文献
37.
M. R. Jamali M. Dehyadegari A. Arami C. Lucas Z. Navabi 《Neural computing & applications》2010,19(1):13-19
Recent studies show that emotion is a mechanism for fast decision-making in human and other animals. Mathematical models have
been developed for describing emotion in mammals. These models, similar to other bioinspired models, must be implemented in
embedded platforms for industrial and real applications. In this paper, brain emotional learning based intelligent controller,
which is based on mammalian middle brain, is designed and implemented on field-programmable gate arrays, and this emotional
controller is applied for controlling of laboratorial overhead traveling crane in model-free and embedded manner. The main
features of this controller are leaning capability, providing a model-free control algorithm, robustness and the ability to
respond swiftly. By designing appropriate stress signals, a designer can implement a proper trade among control objectives. 相似文献
38.
We describe how Intuitionistic Linear Logic can be used to provide a unified logical account for agents to find and execute
plans. This account supports the modelling of agent interaction, including dialogue; allows agents to be robust to unexpected
events and failures; and supports significant reuse of agent specifications. The framework has been implemented and several
case studies have been considered. Further applications include human–computer interfaces as well as agent interaction in
the semantic web. 相似文献
39.
Carlos Ferreira Lucas Guardalben Tomé Gomes Susana Sargento Paulo Salvador Daniel Robalo Fernando J. Velez 《Journal of Network and Systems Management》2017,25(2):416-456
Nowadays, the prevailing use of networks based on traditional centralized management systems reflects on a fast increase of the management costs. The growth in the number of network equipments and services reinforces the need to distribute the management responsibilities throughout the network devices. In this approach, each device executes common network management functionalities, being part of the overall network management platform. In this paper, we present a Unified Distributed Network Management (UDNM) framework that provides a unified (wired and wireless) management network solution, where further different network services can take part of this infrastructure, e.g., flow monitoring, accurate routing decisions, distributed policies dissemination, etc. This framework is divided in two main components: (A) Situation awareness, which sets up initial information through bootstrapping, discovery, fault-management process and exchange of management information; (B) Autonomic Decision System (ADS) that performs distributed decisions in the network with incomplete information. We deploy the UDNM framework in a testbed which involves two cities (\(\approx\)250 km between), different standards (IEEE 802.3, IEEE 802.11 and IEEE 802.16e) and network technologies, such as, wired virtual grid, wireless ad-hoc gateways, ad-hoc mobile access devices. The UDNM framework integrates management functionalities into the managed devices, proving to be a lightweight and easy-respond framework. The performance analysis shows that the UDNM framework is feasible to unify devices management functionalities and to take accurate decisions on top of a real network. 相似文献
40.
Distributed planning and control systems for the virtual enterprise: organizational requirements and development life-cycle 总被引:9,自引:2,他引:7
Anto´nio Lucas Soares Ame´rico Lopes Azevedo Jorge Pinho de Sousa 《Journal of Intelligent Manufacturing》2000,11(3):253-270
This paper describes the requirements analysis and system specification of an Order Promise module to be used as part of a broader Decision Support System for production and operations planning of a Virtual Enterprise. This work is part of a broader project with a particular focus on the microelectronics industry which is a good example of Virtual Enterprise, and where a quick response to the customers needs and to unpredictable changes in production conditions is considered a major factor for success. First, the analysis and specification are presented within a development framework that involves the study of organizational issues of semiconductor enterprises. The use of ontological engineering for supporting the communication and shared understanding of the system concepts is explained and a virtual enterprise ontology is outlined. Following the clarification of the concept of virtual enterprise, the generic techno-organizational requirements for the information system are derived. Finally, a specification of the global planning module and a more detailed one regarding the order promise module is presented. 相似文献