全文获取类型
收费全文 | 4361篇 |
免费 | 333篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 31篇 |
综合类 | 2篇 |
化学工业 | 1189篇 |
金属工艺 | 44篇 |
机械仪表 | 79篇 |
建筑科学 | 167篇 |
矿业工程 | 8篇 |
能源动力 | 165篇 |
轻工业 | 1003篇 |
水利工程 | 45篇 |
石油天然气 | 11篇 |
无线电 | 217篇 |
一般工业技术 | 648篇 |
冶金工业 | 99篇 |
原子能技术 | 18篇 |
自动化技术 | 975篇 |
出版年
2024年 | 5篇 |
2023年 | 51篇 |
2022年 | 61篇 |
2021年 | 255篇 |
2020年 | 151篇 |
2019年 | 192篇 |
2018年 | 196篇 |
2017年 | 178篇 |
2016年 | 199篇 |
2015年 | 154篇 |
2014年 | 231篇 |
2013年 | 379篇 |
2012年 | 327篇 |
2011年 | 379篇 |
2010年 | 263篇 |
2009年 | 240篇 |
2008年 | 221篇 |
2007年 | 218篇 |
2006年 | 140篇 |
2005年 | 130篇 |
2004年 | 124篇 |
2003年 | 97篇 |
2002年 | 82篇 |
2001年 | 46篇 |
2000年 | 45篇 |
1999年 | 42篇 |
1998年 | 54篇 |
1997年 | 41篇 |
1996年 | 25篇 |
1995年 | 24篇 |
1994年 | 18篇 |
1993年 | 15篇 |
1992年 | 17篇 |
1991年 | 20篇 |
1990年 | 11篇 |
1989年 | 13篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有4701条查询结果,搜索用时 140 毫秒
111.
Virginia Francisco Pablo Gervás Federico Peinado 《Knowledge and Information Systems》2010,25(3):421-443
With the advent of affective computing, the task of adequately identifying, representing and processing the emotional connotations
of text has acquired importance. Two problems facing this task are addressed in this paper: the composition of sentence emotion
from word emotion, and a representation of emotion that allows easy conversion between existing computational representations.
The emotion of a sentence of text should be derived by composition of the emotions of the words in the sentence, but no method
has been proposed so far to model this compositionality. Of the various existing approaches for representing emotions, some
are better suited for some problems and some for others, but there is no easy way of converting from one to another. This
paper presents a system that addresses these two problems by reasoning with two ontologies implemented with Semantic Web technologies:
one designed to represent word dependency relations within a sentence, and one designed to represent emotions. The ontology
of word dependency relies on roles to represent the way emotional contributions project over word dependencies. By applying
automated classification of mark-up results in terms of the emotion ontology the system can interpret unrestricted input in
terms of a restricted set of concepts for which particular rules are provided. The rules applied at the end of the process
provide configuration parameters for a system for emotional voice synthesis. 相似文献
112.
Francisco J. Pino César Pardo Félix García Mario Piattini 《Information and Software Technology》2010,52(10):1044-1061
ContextDiagnosing processes in a small company requires process assessment practices which give qualitative and quantitative results; these should offer an overall view of the process capability. The purpose is to obtain relevant information about the running of processes, for use in their control and improvement. However, small organizations have some problems in running process assessment, due to their specific characteristics and limitations.ObjectiveThis paper presents a methodology for assessing software processes which assist the activity of software process diagnosis in small organizations. There is an attempt to address issues such as the fact that: (i) process assessment is expensive and typically requires major company resources and (ii) many light assessment methods do not provide information that is detailed enough for diagnosing and improving processes.MethodTo achieve all this, the METvalCOMPETISOFT assessment methodology was developed. This methodology: (i) incorporates the strategy of internal assessments known as rapid assessment, meaning that these assessments do not take up too much time or use an excessive quantity of resources, nor are they too rigorous and (ii) meets all the requirements described in the literature for an assessment proposal which is customized to the typical features of small companies.ResultsThis paper also describes the experience of the application of this methodology in eight small software organizations that took part in the COMPETISOFT project. The results obtained show that this approach allows us to obtain reliable information about the strengths and weaknesses of software processes, along with information to companies on opportunities for improvement.ConclusionThe assessment methodology proposed sets out the elements needed to assist with diagnosing the process in small organizations step-by-step while seeking to make its application economically feasible in terms of resources and time. From the initial application it may be seen that this assessment methodology can be useful, practical and suitable for diagnosing processes in this type of organizations. 相似文献
113.
Carlos Valle Francisco Saravia Héctor Allende Raúl Monge César Fernández 《Neural Processing Letters》2010,32(3):277-291
Ensemble learning has gained considerable attention in different tasks including regression, classification and clustering. Adaboost and Bagging are two popular approaches used to train these models. The former provides accurate estimations in regression settings but is computationally expensive because of its inherently sequential structure, while the latter is less accurate but highly efficient. One of the drawbacks of the ensemble algorithms is the high computational cost of the training stage. To address this issue, we propose a parallel implementation of the Resampling Local Negative Correlation (RLNC) algorithm for training a neural network ensemble in order to acquire a competitive accuracy like that of Adaboost and an efficiency comparable to that of Bagging. We test our approach on both synthetic and real datasets from the UCI and Statlib repositories for the regression task. In particular, our fine-grained parallel approach allows us to achieve a satisfactory balance between accuracy and parallel efficiency. 相似文献
114.
Simulation of complex mechatronic systems like an automobile, involving mechanical components as well as actuators and active
electronic control devices, can be accomplished by combining tools that deal with the simulation of the different subsystems.
In this sense, it is often desirable to couple a multibody simulation software (for the mechanical simulation) with external
numerical computing environments and block diagram simulators (for the modeling and simulation of nonmechanical components). 相似文献
115.
In this paper we present adaptive algorithms for solving the uniform continuous piecewise affine approximation problem (UCPA)
in the case of Lipschitz or convex functions. The algorithms are based on the tree approximation (adaptive splitting) procedure.
The uniform convergence is achieved by means of global optimization techniques for obtaining tight upper bounds of the local
error estimate (splitting criterion). We give numerical results in the case of the function distance to 2D and 3D geometric
bodies. The resulting trees can retrieve the values of the target function in a fast way. 相似文献
116.
A new fast prototype selection method based on clustering 总被引:2,自引:1,他引:1
J. Arturo Olvera-López J. Ariel Carrasco-Ochoa J. Francisco Martínez-Trinidad 《Pattern Analysis & Applications》2010,13(2):131-141
In supervised classification, a training set T is given to a classifier for classifying new prototypes. In practice, not all information in T is useful for classifiers, therefore, it is convenient to discard irrelevant prototypes from T. This process is known as prototype selection, which is an important task for classifiers since through this process the
time for classification or training could be reduced. In this work, we propose a new fast prototype selection method for large
datasets, based on clustering, which selects border prototypes and some interior prototypes. Experimental results showing
the performance of our method and comparing accuracy and runtimes against other prototype selection methods are reported. 相似文献
117.
Francisco J. Rubio Francisco J. Valero Jose Luis Suñer Vicente Mata 《Asian journal of control》2010,12(4):468-479
This paper addresses the solution of smooth trajectory planning for industrial robots in environments with obstacles using a direct method, creating the trajectory gradually as the robot moves. The presented method deals with the uncertainties associated with the lack of knowledge of kinematic properties of intermediate via‐points since they are generated as the algorithm evolves looking for the solution. Several cost functions are also proposed, which use the time that has been calculated to guide the robot motion. The method has been applied successfully to a PUMA 560 robot and four operational parameters (execution time, computational time, distance travelled and number of configurations) have been computed to study the properties and influence of each cost function on the trajectory obtained. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society 相似文献
118.
Francisco Louzada Osvaldo Anacleto-Junior Cecilia Candolo Josimara Mazucheli 《Expert systems with applications》2011,38(10):12717-12720
Credit scoring modelling comprises one of the leading formal tools for supporting the granting of credit. Its core objective consists of the generation of a score by means of which potential clients can be listed in the order of the probability of default. A critical factor is whether a credit scoring model is accurate enough in order to provide correct classification of the client as a good or bad payer. In this context the concept of bootstraping aggregating (bagging) arises. The basic idea is to generate multiple classifiers by obtaining the predicted values from the fitted models to several replicated datasets and then combining them into a single predictive classification in order to improve the classification accuracy. In this paper we propose a new bagging-type variant procedure, which we call poly-bagging, consisting of combining predictors over a succession of resamplings. The study is derived by credit scoring modelling. The proposed poly-bagging procedure was applied to some different artificial datasets and to a real granting of credit dataset up to three successions of resamplings. We observed better classification accuracy for the two-bagged and the three-bagged models for all considered setups. These results lead to a strong indication that the poly-bagging approach may promote improvement on the modelling performance measures, while keeping a flexible and straightforward bagging-type structure easy to implement. 相似文献
119.
Francisco Almeida Domingo Giménez Jose J. López-Espín 《The Journal of supercomputing》2011,58(3):292-301
This paper presents a parameterized shared-memory scheme for parameterized metaheuristics. The use of a parameterized metaheuristic
facilitates experimentation with different metaheuristics and hybridation/combinations to adapt them to the particular problem
we are working with. Due to the large number of experiments necessary for the metaheuristic selection and tuning, parallelism
should be used to reduce the execution time. To obtain parallel versions of the metaheuristics and to adapt them to the characteristics
of the parallel system, a unified parameterized shared-memory scheme is developed. Given a particular computational system
and fixed parameters for the sequential metaheuristic, the appropriate selection of parameters in the unified parallel scheme
eases the development of parallel efficient metaheuristics. 相似文献
120.
MELM-GRBF: A modified version of the extreme learning machine for generalized radial basis function neural networks 总被引:3,自引:0,他引:3
Francisco Fernández-NavarroAuthor Vitae César Hervás-MartínezAuthor VitaeJavier Sanchez-MonederoAuthor Vitae Pedro Antonio GutiérrezAuthor Vitae 《Neurocomputing》2011,74(16):2502-2510
In this paper, we propose a methodology for training a new model of artificial neural network called the generalized radial basis function (GRBF) neural network. This model is based on generalized Gaussian distribution, which parametrizes the Gaussian distribution by adding a new parameter τ. The generalized radial basis function allows different radial basis functions to be represented by updating the new parameter τ. For example, when GRBF takes a value of τ=2, it represents the standard Gaussian radial basis function. The model parameters are optimized through a modified version of the extreme learning machine (ELM) algorithm. In the methodology proposed (MELM-GRBF), the centers of each GRBF were taken randomly from the patterns of the training set and the radius and τ values were determined analytically, taking into account that the model must fulfil two constraints: locality and coverage. An thorough experimental study is presented to test its overall performance. Fifteen datasets were considered, including binary and multi-class problems, all of them taken from the UCI repository. The MELM-GRBF was compared to ELM with sigmoidal, hard-limit, triangular basis and radial basis functions in the hidden layer and to the ELM-RBF methodology proposed by Huang et al. (2004) [1]. The MELM-GRBF obtained better results in accuracy than the corresponding sigmoidal, hard-limit, triangular basis and radial basis functions for almost all datasets, producing the highest mean accuracy rank when compared with these other basis functions for all datasets. 相似文献