全文获取类型
收费全文 | 3182篇 |
免费 | 199篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 24篇 |
综合类 | 4篇 |
化学工业 | 809篇 |
金属工艺 | 28篇 |
机械仪表 | 55篇 |
建筑科学 | 122篇 |
矿业工程 | 10篇 |
能源动力 | 129篇 |
轻工业 | 521篇 |
水利工程 | 35篇 |
石油天然气 | 8篇 |
无线电 | 275篇 |
一般工业技术 | 452篇 |
冶金工业 | 79篇 |
原子能技术 | 34篇 |
自动化技术 | 798篇 |
出版年
2024年 | 1篇 |
2023年 | 29篇 |
2022年 | 101篇 |
2021年 | 158篇 |
2020年 | 88篇 |
2019年 | 106篇 |
2018年 | 117篇 |
2017年 | 120篇 |
2016年 | 151篇 |
2015年 | 103篇 |
2014年 | 192篇 |
2013年 | 274篇 |
2012年 | 262篇 |
2011年 | 259篇 |
2010年 | 199篇 |
2009年 | 202篇 |
2008年 | 182篇 |
2007年 | 165篇 |
2006年 | 96篇 |
2005年 | 92篇 |
2004年 | 71篇 |
2003年 | 80篇 |
2002年 | 57篇 |
2001年 | 27篇 |
2000年 | 26篇 |
1999年 | 34篇 |
1998年 | 30篇 |
1997年 | 23篇 |
1996年 | 27篇 |
1995年 | 21篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1978年 | 4篇 |
排序方式: 共有3383条查询结果,搜索用时 953 毫秒
71.
Partial discharges are a transient phenomena whose measurement is remarkably important for electrical equipment diagnosis and maintenance. These discharges appear in the measurement circuit as very narrow current pulses of some nanoseconds. Therefore, discharge pulse detection is a particularly difficult problem, especially because they are superposed on the high voltage waveforms that cause them. In this paper, we present an inductively coupled probe able to measure this physical phenomenon by means of a very simple and inexpensive device that can be installed in the equipment under test. After modeling the probe, its response will be compared to that of commercial devices using both calibrated discharges and partial discharges occurring at real power. 相似文献
72.
Weighted Max-SAT is the optimization version of SAT and many important problems can be naturally encoded as such. Solving weighted Max-SAT is an important problem from both a theoretical and a practical point of view. In recent years, there has been considerable interest in finding efficient solving techniques. Most of this work focuses on the computation of good quality lower bounds to be used within a branch and bound DPLL-like algorithm. Most often, these lower bounds are described in a procedural way. Because of that, it is difficult to realize the logic that is behind.In this paper we introduce an original framework for Max-SAT that stresses the parallelism with classical SAT. Then, we extend the two basic SAT solving techniques: search and inference. We show that many algorithmic tricks used in state-of-the-art Max-SAT solvers are easily expressible in logical terms in a unified manner, using our framework.We also introduce an original search algorithm that performs a restricted amount of weighted resolution at each visited node. We empirically compare our algorithm with a variety of solving alternatives on several benchmarks. Our experiments, which constitute to the best of our knowledge the most comprehensive Max-SAT evaluation ever reported, demonstrate the practical usability of our approach. 相似文献
73.
Cáceres-Criado Irene García-Molina Diego Francisco Mesas-Carrascosa Francisco Javier Triviño-Tarradas Paula 《Virtual Reality》2023,27(2):967-983
Virtual Reality - Virtual reconstruction is defined as the visual recovery of a building or object through the creation of a three-dimensional model of the asset to be reconstructed, in a... 相似文献
74.
There have been many linear regression models proposed to analyze mixture experiments including the Scheffé model, the slack-variable model, and the Kronecker model. The use of the slack-variable model is somewhat controversial within the mixture experiment research community. However, in situations that the slack-variable ingredient is used to fill in the formulation and the remaining ingredients have constraints such that they can be chosen independently of one another, the slack-variable model is extremely popular by practitioners mainly due to the ease of interpretation. In this article, we advocate that for some mixture experiments the slack-variable model has appealing properties including numerical stability and better prediction accuracy when model-term selection is performed. We also explain how the effects of the slack-variable model components should be interpreted and how easy it is for practitioners to understand the components effects. We also investigate how to choose the slack-variable component, what transformation should be used to reduce collinearity, and under what circumstances the slack-variable model should be preferred. Both simulation and practical examples are provided to support the conclusions. 相似文献
75.
Javier Sánchez-Monedero Pedro A. Gutiérrez F. Fernández-Navarro C. Hervás-Martínez 《Neural Processing Letters》2011,34(2):101-116
Recently, a multi-objective Sensitivity–Accuracy based methodology has been proposed for building classifiers for multi-class problems. This technique is especially suitable for imbalanced and multi-class datasets. Moreover, the high computational cost of multi-objective approaches is well known so more efficient alternatives must be explored. This paper presents an efficient alternative to the Pareto based solution when considering both Minimum Sensitivity and Accuracy in multi-class classifiers. Alternatives are implemented by extending the Evolutionary Extreme Learning Machine algorithm for training artificial neural networks. Experiments were performed to select the best option after considering alternative proposals and related methods. Based on the experiments, this methodology is competitive in Accuracy, Minimum Sensitivity and efficiency. 相似文献
76.
Pawe Kuakowski Javier Vales-Alonso Esteban Egea-Lpez Wiesaw Ludwin Joan García-Haro 《Computers & Electrical Engineering》2010,36(6):1181-1186
Among the large number of contributions concerning the localization techniques for wireless sensor networks (WSNs), there is still no simple, energy and cost efficient solution suitable in outdoor scenarios. In this paper, a technique based on antenna arrays and angle-of-arrival (AoA) measurements is carefully discussed. While the AoA algorithms are rarely considered for WSNs due to the large dimensions of directional antennas, some system configurations are investigated that can be easily incorporated in pocket-size wireless devices.A heuristic weighting function that enables decreasing the location errors is introduced. Also, the detailed performance analysis of the presented system is provided. The localization accuracy is validated through realistic Monte-Carlo simulations that take into account the specificity of propagation conditions in WSNs as well as the radio noise effects. Finally, trade-offs between the accuracy, localization time and the number of anchors in a network are addressed. 相似文献
77.
We present and analyze an unsupervised method for Word Sense Disambiguation (WSD). Our work is based on the method presented
by McCarthy et al. in 2004 for finding the predominant sense of each word in the entire corpus. Their maximization algorithm allows weighted
terms (similar words) from a distributional thesaurus to accumulate a score for each ambiguous word sense, i.e., the sense
with the highest score is chosen based on votes from a weighted list of terms related to the ambiguous word. This list is
obtained using the distributional similarity method proposed by Lin Dekang to obtain a thesaurus. In the method of McCarthy
et al., every occurrence of the ambiguous word uses the same thesaurus, regardless of the context where the ambiguous word occurs.
Our method accounts for the context of a word when determining the sense of an ambiguous word by building the list of distributed
similar words based on the syntactic context of the ambiguous word. We obtain a top precision of 77.54% of accuracy versus
67.10% of the original method tested on SemCor. We also analyze the effect of the number of weighted terms in the tasks of
finding the Most Frecuent Sense (MFS) and WSD, and experiment with several corpora for building the Word Space Model. 相似文献
78.
Luis de-Marcos José Ramón Hilera Roberto Barchino Lourdes Jiménez José Javier Martínez José Antonio Gutiérrez José María Gutiérrez Salvador Otón 《Computers & Education》2010
Mobile learning is considered an evolution of e-learning that embraces the ubiquitous nature of current computational systems in order to improve teaching and learning. Within this context it is possible to develop mobile applications oriented to learning, but it is also important to assess to what extent such applications actually work. In this paper we present a new tool designed to reinforce students’ knowledge by means of self-assessment. Improvement in student achievement was evaluated and an attitudinal survey was also carried out to measure student attitudes towards this new tool. Three different experimental groups were selected for this research, with students aged from 14 to 21 years old, including high-school and university students. Results show that this kind of tool improves student achievement, especially amongst younger learners, with a relatively low impact on current teaching activities and methodology. 相似文献
79.
New techniques for simulating high performance MPI applications on large storage networks 总被引:1,自引:0,他引:1
Alberto Núñez Javier Fernández Jose D. Garcia Félix Garcia Jesús Carretero 《The Journal of supercomputing》2010,51(1):40-57
In this work, we propose new techniques to analyze the behavior, the performance, and specially the scalability of High Performance
Computing (in short, HPC) applications on different computing architectures. Our final objective is to test applications using
a wide range of architectures (real or merely designed) and scaling it to any number of nodes or components. This paper presents
a new simulation framework, called SIMCAN, for HPC architectures. The main characteristic of the proposed simulation framework
is the ability to be configured for simulating a wide range of possible architectures that involve any number of components.
SIMCAN is developed to simulate complete HPC architectures, but putting special emphasis on the storage and network subsystems.
The SIMCAN framework can handle complete components (nodes, racks, switches, routers, etc.), but also key elements of the
storage and network subsystems (disks, caches, sockets, file systems, schedulers, etc.). We also propose several methods to
implement the behavior of HPC applications. Each method has its own advantages and drawbacks. In order to evaluate the possibilities
and the accuracy of the SIMCAN framework, we have tested it by executing a HPC application called BIPS3D on a hardware-based
computing cluster and on a modeled environment that represent the real cluster. We also checked the scalability of the application
using this kind of architecture by simulating the same application with an increased number of computing nodes. 相似文献
80.
Humanitarian Non-Governmental Organisations (NGOs) play a growing role in the response to natural disasters, but despite being largely demanded, there is no available decision support system (DSS) specifically designed to address their problem. In this paper we present a decision support system (DSS) to aid those Humanitarian NGOs concerned with the response to natural disasters. Such a DSS has been designed avoiding sophisticated methodologies that may exceed the infrastructural requirements and constraints of emergency management by NGOs. A data-based, two-level knowledge methodology which allows damage assessment of multiple disaster scenarios is presented in order to address that problem. Validation results show viability of our approach. 相似文献