全文获取类型
收费全文 | 3618篇 |
免费 | 259篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 35篇 |
综合类 | 6篇 |
化学工业 | 863篇 |
金属工艺 | 122篇 |
机械仪表 | 113篇 |
建筑科学 | 182篇 |
矿业工程 | 16篇 |
能源动力 | 142篇 |
轻工业 | 686篇 |
水利工程 | 30篇 |
石油天然气 | 11篇 |
无线电 | 208篇 |
一般工业技术 | 563篇 |
冶金工业 | 196篇 |
原子能技术 | 26篇 |
自动化技术 | 685篇 |
出版年
2024年 | 5篇 |
2023年 | 41篇 |
2022年 | 51篇 |
2021年 | 142篇 |
2020年 | 115篇 |
2019年 | 133篇 |
2018年 | 161篇 |
2017年 | 135篇 |
2016年 | 180篇 |
2015年 | 133篇 |
2014年 | 182篇 |
2013年 | 291篇 |
2012年 | 256篇 |
2011年 | 294篇 |
2010年 | 199篇 |
2009年 | 216篇 |
2008年 | 182篇 |
2007年 | 166篇 |
2006年 | 135篇 |
2005年 | 123篇 |
2004年 | 104篇 |
2003年 | 78篇 |
2002年 | 74篇 |
2001年 | 46篇 |
2000年 | 37篇 |
1999年 | 36篇 |
1998年 | 55篇 |
1997年 | 30篇 |
1996年 | 36篇 |
1995年 | 30篇 |
1994年 | 19篇 |
1993年 | 26篇 |
1992年 | 19篇 |
1991年 | 15篇 |
1990年 | 9篇 |
1989年 | 13篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 13篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1977年 | 14篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1965年 | 2篇 |
排序方式: 共有3884条查询结果,搜索用时 93 毫秒
111.
Pérez-Ortiz Juan Antonio Calera-Rubio Jorge Forcada Mikel L. 《Neural Processing Letters》2001,14(2):127-140
Arithmetic coding is one of the most outstanding techniques for lossless data compression. It attains its good performance with the help of a probability model which indicates at each step the probability of occurrence of each possible input symbol given the current context. The better this model, the greater the compression ratio achieved. This work analyses the use of discrete-time recurrent neural networks and their capability for predicting the next symbol in a sequence in order to implement that model. The focus of this study is on online prediction, a task much harder than the classical offline grammatical inference with neural networks. The results obtained show that recurrent neural networks have no problem when the sequences come from the output of a finite-state machine, easily giving high compression ratios. When compressing real texts, however, the dynamics of the sequences seem to be too complex to be learned online correctly by the net. 相似文献
112.
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
113.
Agostinho de Medeiros Brito Junior Adri?o Duarte Dória Neto Jorge Dantas de Melo Luiz Marcos Garcia Goncalves 《Neural Networks, IEEE Transactions on》2008,19(6):1130-1140
In this paper, we propose a multiresolution approach for surface reconstruction from clouds of unorganized points representing an object surface in 3-D space. The proposed method uses a set of mesh operators and simple rules for selective mesh refinement, with a strategy based on Kohonen's self-organizing map (SOM). Basically, a self-adaptive scheme is used for iteratively moving vertices of an initial simple mesh in the direction of the set of points, ideally the object boundary. Successive refinement and motion of vertices are applied leading to a more detailed surface, in a multiresolution, iterative scheme. Reconstruction was experimented on with several point sets, including different shapes and sizes. Results show generated meshes very close to object final shapes. We include measures of performance and discuss robustness. 相似文献
114.
Standards-development organizations (SDOs) comprise participants from large and small companies, academia, and the open source community. The participants come with varying backgrounds with regard to copyright and patents in the areas that are being standardized, and the SDOs must deal with these issues in ways that both satisfy the participants (and their employers) and result in useful standards. Each SDO — including the IEEE — has its own intellectual property (IP) policy. This issue, we look at how the IETF handles IP, in an overview cowritten by an attorney who has represented the IETF for some years and the current IETF Chair. 相似文献
115.
Seyed Ali Modarres Najafabadi József Kövecses Jorge Angeles 《Multibody System Dynamics》2008,20(2):163-176
This paper outlines a novel approach to the modeling and analysis of impact involving multibody systems. This approach is
based on an analysis of energy absorption and restitution during impact, using a decomposition of the kinetic energy, which
decouples the parts associated with the spaces of admissible and constrained motions of the underlying unilateral constraints.
Such a decomposition turns out to be useful in the analysis of energy dissipation during impact, and leads to a generalized
definition of the energetic coefficient of restitution, which targets particularly collisions in multibody systems. The applicability
of the approach reported is investigated by conducting an experimental study on a robotic testbed. It is shown that impact
between multibody systems is considerably affected not only by the local dynamics characteristics of the interacting bodies,
but also the configuration of the whole multibody system. The results reported here show that our decomposition can offer
a sound characterization of impact in several problems of multibody systems. 相似文献
116.
117.
118.
Tristan M. Behrens Jürgen Dix 《Annals of Mathematics and Artificial Intelligence》2007,51(2-4):81-121
We introduce a class of Petri nets, simple logic Petri nets (SLPN), that are based on logical expressions. We show how this type of nets can be efficiently mapped into logic programs with negation: the corresponding answer sets describe interleaved executions of the underlying nets (Theorem 1). The absence of an answer set indicates a deadlock situation. We also show how to correctly model and specify AgentSpeak agents and multi-agent systems with SLPN’s (Theorem 2). Both theorems allow us to solve the task of model checking AgentSpeak multi-agent systems by computing answer sets of the obtained logic program with any ASP system. 相似文献
119.
Guidelines for the incremental identification of aspects in requirements specifications 总被引:1,自引:0,他引:1
Jorge García-Duque Martín López-Nores José J. Pazos-Arias Ana Fernández-Vilas Rebeca P. Díaz-Redondo Alberto Gil-Solla Manuel Ramos-Cabrer Yolanda Blanco-Fernández 《Requirements Engineering》2006,11(4):239-263
The desired principle of separation of concerns in software development can be jeopardized by the so-called crosscutting concerns, which tend to be scattered over (and tangled with) the functionality of the modular units of a system. The correct identification of such concerns (and their encapsulation into separate artifacts) is thereby considered a way to improve software understanding and evolution. Pursuing a proper management of concerns from the requirements engineering stage can greatly benefit the entire software life-cycle. In this paper, we propose conceptual guidelines on how to perform the identification of crosscutting concerns in the process of building requirements specifications. We argue that the identification must be carried out in an incremental way, to encapsulate apart the crosscutting concerns even if they have not emerged completely yet.
相似文献
Yolanda Blanco-FernándezEmail: |