全文获取类型
收费全文 | 4720篇 |
免费 | 349篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 34篇 |
综合类 | 2篇 |
化学工业 | 1363篇 |
金属工艺 | 50篇 |
机械仪表 | 86篇 |
建筑科学 | 169篇 |
矿业工程 | 8篇 |
能源动力 | 171篇 |
轻工业 | 1057篇 |
水利工程 | 45篇 |
石油天然气 | 21篇 |
无线电 | 243篇 |
一般工业技术 | 680篇 |
冶金工业 | 113篇 |
原子能技术 | 19篇 |
自动化技术 | 1015篇 |
出版年
2024年 | 6篇 |
2023年 | 52篇 |
2022年 | 143篇 |
2021年 | 270篇 |
2020年 | 169篇 |
2019年 | 204篇 |
2018年 | 206篇 |
2017年 | 187篇 |
2016年 | 205篇 |
2015年 | 161篇 |
2014年 | 242篇 |
2013年 | 397篇 |
2012年 | 347篇 |
2011年 | 399篇 |
2010年 | 277篇 |
2009年 | 248篇 |
2008年 | 240篇 |
2007年 | 228篇 |
2006年 | 153篇 |
2005年 | 137篇 |
2004年 | 132篇 |
2003年 | 101篇 |
2002年 | 86篇 |
2001年 | 56篇 |
2000年 | 48篇 |
1999年 | 46篇 |
1998年 | 61篇 |
1997年 | 44篇 |
1996年 | 34篇 |
1995年 | 26篇 |
1994年 | 20篇 |
1993年 | 19篇 |
1992年 | 18篇 |
1991年 | 20篇 |
1990年 | 15篇 |
1989年 | 15篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有5076条查询结果,搜索用时 46 毫秒
91.
In this paper we study a problem of sequencing jobs in a machine with programmed preventive maintenance and sequence-dependent set-up times. The problem combines two NP-hard problems, so we propose a heuristic method for solving it, which hybridizes multi-start strategies with Tabu Search. We compare our method with the only published metaheuristic algorithm for this problem on a set of 420 instances. The comparison favors the method developed in this work, showing that is able to find high quality solutions in very short computational times. 相似文献
92.
Francisco P. Romero Pascual Julián-Iranzo Andrés Soto Mateus Ferreira-Satler Juan Gallardo-Casero 《Language Resources and Evaluation》2013,47(1):151-178
Web 2.0 provides user-friendly tools that allow persons to create and publish content online. User generated content often takes the form of short texts (e.g., blog posts, news feeds, snippets, etc). This has motivated an increasing interest on the analysis of short texts and, specifically, on their categorisation. Text categorisation is the task of classifying documents into a certain number of predefined categories. Traditional text classification techniques are mainly based on word frequency statistical analysis and have been proved inadequate for the classification of short texts where word occurrence is too small. On the other hand, the classic approach to text categorization is based on a learning process that requires a large number of labeled training texts to achieve an accurate performance. However labeled documents might not be available, when unlabeled documents can be easily collected. This paper presents an approach to text categorisation which does not need a pre-classified set of training documents. The proposed method only requires the category names as user input. Each one of these categories is defined by means of an ontology of terms modelled by a set of what we call proximity equations. Hence, our method is not category occurrence frequency based, but highly depends on the definition of that category and how the text fits that definition. Therefore, the proposed approach is an appropriate method for short text classification where the frequency of occurrence of a category is very small or even zero. Another feature of our method is that the classification process is based on the ability of an extension of the standard Prolog language, named Bousi~Prolog , for flexible matching and knowledge representation. This declarative approach provides a text classifier which is quick and easy to build, and a classification process which is easy for the user to understand. The results of experiments showed that the proposed method achieved a reasonably useful performance. 相似文献
93.
Influence diagnostics in beta regression 总被引:1,自引:0,他引:1
Patrícia L. Espinheira Francisco Cribari-Neto 《Computational statistics & data analysis》2008,52(9):4417-4431
We consider the issue of assessing influence of observations in the class of beta regression models, which is useful for modelling random variables that assume values in the standard unit interval and are affected by independent variables. We propose a Cook-like distance and also measures of local influence under different perturbation schemes. Applications using real data are presented. 相似文献
94.
User simulation in a stochastic dialog system 总被引:1,自引:1,他引:0
We present a new methodology of user simulation applied to the evaluation and refinement of stochastic dialog systems. Common weaknesses of these systems are the scarceness of the training corpus and the cost of an evaluation made by real users. We have considered the user simulation technique as an alternative way of testing and improving our dialog system. We have developed a new dialog manager that plays the role of the user. This user dialog manager incorporates several knowledge sources, combining statistical and heuristic information in order to define its dialog strategy. Once the user simulator is integrated into the dialog system, it is possible to enhance the dialog models by an automatic strategy learning. We have performed an extensive evaluation, achieving a slight but clear improvement of the dialog system. 相似文献
95.
Visual Navigation for Mobile Robots: A Survey 总被引:4,自引:0,他引:4
Francisco Bonin-Font Alberto Ortiz Gabriel Oliver 《Journal of Intelligent and Robotic Systems》2008,53(3):263-296
Mobile robot vision-based navigation has been the source of countless research contributions, from the domains of both vision
and control. Vision is becoming more and more common in applications such as localization, automatic map construction, autonomous
navigation, path following, inspection, monitoring or risky situation detection. This survey presents those pieces of work,
from the nineties until nowadays, which constitute a wide progress in visual navigation techniques for land, aerial and autonomous
underwater vehicles. The paper deals with two major approaches: map-based navigation and mapless navigation. Map-based navigation has been in turn subdivided in metric map-based navigation and topological map-based navigation. Our outline to mapless navigation includes reactive techniques based on qualitative characteristics extraction, appearance-based
localization, optical flow, features tracking, plane ground detection/tracking, etc... The recent concept of visual sonar has also been revised.
This work is partially supported by DPI 2005-09001-C03-02 and FEDER funding. 相似文献
96.
Adaptation and application of multi-objective evolutionary algorithms for rule reduction and parameter tuning of fuzzy rule-based systems 总被引:7,自引:7,他引:0
María José Gacto Rafael Alcalá Francisco Herrera 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2009,13(5):419-436
Recently, multi-objective evolutionary algorithms have been applied to improve the difficult tradeoff between interpretability
and accuracy of fuzzy rule-based systems. It is known that both requirements are usually contradictory, however, these kinds
of algorithms can obtain a set of solutions with different trade-offs. This contribution analyzes different application alternatives
in order to attain the desired accuracy/interpr-etability balance by maintaining the improved accuracy that a tuning of membership
functions could give but trying to obtain more compact models. In this way, we propose the use of multi-objective evolutionary
algorithms as a tool to get almost one improved solution with respect to a classic single objective approach (a solution that
could dominate the one obtained by such algorithm in terms of the system error and number of rules). To do that, this work
presents and analyzes the application of six different multi-objective evolutionary algorithms to obtain simpler and still
accurate linguistic fuzzy models by performing rule selection and a tuning of the membership functions. The results on two
different scenarios show that the use of expert knowledge in the algorithm design process significantly improves the search
ability of these algorithms and that they are able to improve both objectives together, obtaining more accurate and at the
same time simpler models with respect to the single objective based approach.
相似文献
María José Gacto (Corresponding author)Email: |
Rafael AlcaláEmail: |
Francisco HerreraEmail: |
97.
Gustavo Olague Cynthia B. Pérez Francisco Fernández Evelyne Lutton 《Artificial Life and Robotics》2009,13(2):585-596
This article presents an adaptive approach to improving the infection algorithm that we have used to solve the dense stereo
matching problem. The algorithm presented here incorporates two different epidemic automata along a single execution of the
infection algorithm. The new algorithm attempts to provide a general behavior of guessing the best correspondence between
a pair of images. Our aim is to provide a new strategy inspired by evolutionary computation, which combines the behaviors
of both automata into a single correspondence problem. The new algorithm will decide which automata will be used based on
the transmission of information and mutation, as well as the attributes, texture, and geometry, of the input images. This
article gives details about how the rules used in the infection algorithm are coded. Finally, we show experiments with a real
stereo pair, as well as with a standard test bed, to show how the infection algorithm works. 相似文献
98.
Sujoy Basu Lauro Beltrão Costa Francisco Brasileiro Sujata Banerjee Puneet Sharma Sung-Ju Lee 《Peer-to-Peer Networking and Applications》2009,2(4):348-366
Large scale grid computing systems may provide multitudinous services, from different providers, whose quality of service
will vary. Moreover, services are deployed and undeployed in the grid with no central coordination. Thus, to find out the
most suitable service to fulfill their needs, or to find the most suitable set of resources on which to deploy their services,
grid users must resort to a Grid Information Service (GIS). This service allows users to submit rich queries that are normally
composed of multiple attributes and range operations. The ability to efficiently execute complex searches in a scalable and
reliable way is a key challenge for current GIS designs. Scalability issues are normally dealt with by using peer-to-peer
technologies. However, the more reliable peer-to-peer approaches do not cater for rich queries in a natural way. On the other
hand, approaches that can easily support these rich queries are less robust in the presence of failures. In this paper we
present the design of NodeWiz, a GIS that allows multi-attribute range queries to be performed efficiently in a distributed
manner, while maintaining load balance and resilience to failures. 相似文献
99.
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
100.