全文获取类型
收费全文 | 1143篇 |
免费 | 114篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 14篇 |
综合类 | 2篇 |
化学工业 | 355篇 |
金属工艺 | 17篇 |
机械仪表 | 24篇 |
建筑科学 | 40篇 |
矿业工程 | 4篇 |
能源动力 | 55篇 |
轻工业 | 111篇 |
水利工程 | 10篇 |
石油天然气 | 1篇 |
无线电 | 121篇 |
一般工业技术 | 220篇 |
冶金工业 | 37篇 |
原子能技术 | 9篇 |
自动化技术 | 239篇 |
出版年
2023年 | 22篇 |
2022年 | 64篇 |
2021年 | 83篇 |
2020年 | 50篇 |
2019年 | 32篇 |
2018年 | 59篇 |
2017年 | 47篇 |
2016年 | 45篇 |
2015年 | 46篇 |
2014年 | 69篇 |
2013年 | 88篇 |
2012年 | 104篇 |
2011年 | 86篇 |
2010年 | 75篇 |
2009年 | 62篇 |
2008年 | 50篇 |
2007年 | 53篇 |
2006年 | 29篇 |
2005年 | 29篇 |
2004年 | 21篇 |
2003年 | 22篇 |
2002年 | 17篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 11篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1259条查询结果,搜索用时 15 毫秒
31.
32.
In recent years, Grid systems and Peer to Peer networks are the most commonly-used solutions to achieve the same goal: the sharing of resources and services in heterogeneous, dynamic, distributed environments. Many studies have proposed hybrid approaches that try to conjugate the advantages of the two models. This paper proposes an architecture that integrates the P2P interaction model in Grid environments, so as to build an open cooperative model wherein Grid entities are composed in a decentralized way. In particular, this paper focuses on a QoS aware discovery algorithm for P2P Grid systems, analyzing protocol and explaining techniques used to improve its performance. 相似文献
33.
We present a method for producing quad‐dominant subdivided meshes, which supports both adaptive refinement and adaptive coarsening. A hierarchical structure is stored implicitly in a standard half‐edge data structure, while allowing us to efficiently navigate through the different level of subdivision. Subdivided meshes contain a majority of quad elements and a moderate amount of triangles and pentagons in the regions of transition across different levels of detail. Topological LOD editing is controlled with local conforming operators, which support both mesh refinement and mesh coarsening. We show two possible applications of this method: we define an adaptive subdivision surface scheme that is topologically and geometrically consistent with the Catmull–Clark subdivision; and we present a remeshing method that produces semi‐regular adaptive meshes. 相似文献
34.
Privacy preserving technologies are likely to become an essential component of adaptive services in pervasive and mobile computing. Although privacy issues have been studied for a long time in computer science as well as in other fields, most studies are focused on the release of data from large repositories. Mobile and pervasive computing pose new challenges, requiring specific formal models for attacks and new privacy preserving techniques. This paper considers a specific pervasive computing scenario, and shows that the application of state-of-the-art techniques for the anonymization of service requests is insufficient to protect the privacy of users. A specific class of attacks, called shadow attacks, is formally defined and a defense technique is proposed. This defense is formally proved to be correct, and its effectiveness is validated by extensive experiments in a simulated environment. 相似文献
35.
We analyze generalization in XCSF and introduce three improvements. We begin by showing that the types of generalizations evolved by XCSF can be influenced by the input range. To explain these results we present a theoretical analysis of the convergence of classifier weights in XCSF which highlights a broader issue. In XCSF, because of the mathematical properties of the Widrow-Hoff update, the convergence of classifier weights in a given subspace can be slow when the spread of the eigenvalues of the autocorrelation matrix associated with each classifier is large. As a major consequence, the system's accuracy pressure may act before classifier weights are adequately updated, so that XCSF may evolve piecewise constant approximations, instead of the intended, and more efficient, piecewise linear ones. We propose three different ways to update classifier weights in XCSF so as to increase the generalization capabilities of XCSF: one based on a condition-based normalization of the inputs, one based on linear least squares, and one based on the recursive version of linear least squares. Through a series of experiments we show that while all three approaches significantly improve XCSF, least squares approaches appear to be best performing and most robust. Finally we show how XCSF can be extended to include polynomial approximations. 相似文献
36.
In this paper we discuss reasoning about reasoning in a multiple agent scenario. We consider agents that are perfect reasoners, loyal, and that can take advantage of both the knowledge and ignorance of other agents. The knowledge representation formalism we use is (full) first order predicate calculus, where different agents are represented by different theories, and reasoning about reasoning is realized via a meta-level representation of knowledge and reasoning. The framework we provide is pretty general: we illustrate it by showing a machine checked solution to the three wisemen puzzle. The agents' knowledge is organized into units: the agent's own knowledge about the world and its knowledge about other agents are units containing object-level knowledge; a unit containing meta-level knowledge embodies the reasoning about reasoning and realizes the link among units. In the paper we illustrate the meta-level architecture we propose for problem solving in a multi-agent scenario; we discuss our approach in relation to the modal one and we compare it with other meta-level architectures based on logic. Finally, we look at a class of applications that can be effectively modeled by exploiting the meta-level approach to reasoning about knowledge and reasoning. 相似文献
37.
38.
We present a decidability result for the model checking of a certain class of properties that can be conveniently expressed
as ground formulae of a first-order temporal fragment. The decidability result is obtained by importing into the context of
model-checking problems some techniques developed for the combination of decision procedures for the satisfiability of constraints.
The general decidability result is then specialized for checking properties of particular interest, such as liveness and safety,
and, for the latter case, a more optimized algorithm has been proposed. 相似文献
39.
José D. Martín Guerrero Daniele Marcelli Emilio Soria-Olivas Flavio Mari José María Martínez-Martínez Isabel Soley Bech Marcelino Martínez-Sober Laura Scatizzi Juan Gómez-Sanchis Andrea Stopper Antonio José Serrano-López Emanuele Gatti 《Expert systems with applications》2012,39(10):8793-8798
Evaluation of patient satisfaction has become an important indicator for assessing health care quality. Fresenius Medical Care (FME) as a global provider of dialysis services through its NephroCare network has a strong interest in monitoring patient satisfaction.The aim of the paper is to test and validate a methodology for detecting a residual area of low satisfaction in dialysis patients.The FME Patient Satisfaction Programme questionnaire was distributed to haemodialysis (HD) patients treated in 335 centers of its network. It contained 79 questions covering various satisfaction aspects regarding Dialysis Unit, Dialysis Arrangement, Nurses, Doctors, etc.To analyse the data provided by the questionnaire, the Self-Organising Map (SOM) method was used. SOM is a neural network model for clustering and projecting high-dimensional data into a low-dimensional space, preserving topological relationships of original high-dimensional data spaces.10,632 HD patients completed the questionnaire. Mean age was 63.05 ± 14.93 years with 56.69% males. Response rate was 66%. Overall level of satisfaction was 1.99 (range from ?3 to +3). On average patients were very satisfied with all issues. Nevertheless, a group of patients, around 60 years old, balanced gender ratio, whose level of satisfaction was lower than 1, were highlighted.In the NephroCare clinics patient satisfaction with service is rather high. While traditional analysis usually stops here, the SOM method allows identification of areas of potential improvement for specific patient groups. 相似文献
40.
Pedersoli E Capotondi F Cocco D Zangrando M Kaulich B Menk RH Locatelli A Mentes TO Spezzani C Sandrin G Bacescu DM Kiskinova M Bajt S Barthelmess M Barty A Schulz J Gumprecht L Chapman HN Nelson AJ Frank M Pivovaroff MJ Woods BW Bogan MJ Hajdu J 《The Review of scientific instruments》2011,82(4):043711
We present a compact modular apparatus with a flexible design that will be operated at the DiProI beamline of the Fermi@Elettra free electron laser (FEL) for performing static and time-resolved coherent diffraction imaging experiments, taking advantage of the full coherence and variable polarization of the short seeded FEL pulses. The apparatus has been assembled and the potential of the experimental setup is demonstrated by commissioning tests with coherent synchrotron radiation. This multipurpose experimental station will be open to general users after installation at the Fermi@Elettra free electron laser in 2011. 相似文献