全文获取类型
收费全文 | 855篇 |
免费 | 81篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 207篇 |
金属工艺 | 23篇 |
机械仪表 | 47篇 |
建筑科学 | 28篇 |
能源动力 | 100篇 |
轻工业 | 190篇 |
水利工程 | 10篇 |
石油天然气 | 8篇 |
无线电 | 24篇 |
一般工业技术 | 125篇 |
冶金工业 | 9篇 |
原子能技术 | 21篇 |
自动化技术 | 135篇 |
出版年
2024年 | 6篇 |
2023年 | 14篇 |
2022年 | 30篇 |
2021年 | 63篇 |
2020年 | 28篇 |
2019年 | 28篇 |
2018年 | 58篇 |
2017年 | 50篇 |
2016年 | 60篇 |
2015年 | 38篇 |
2014年 | 43篇 |
2013年 | 148篇 |
2012年 | 38篇 |
2011年 | 60篇 |
2010年 | 71篇 |
2009年 | 65篇 |
2008年 | 29篇 |
2007年 | 26篇 |
2006年 | 19篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有936条查询结果,搜索用时 15 毫秒
11.
12.
Due to a lot of robot manipulators application in industry, low noise degree is very important criteria for robot manipulator's joints. In this paper, joint noise problem of a robot manipulator with five joints is investigated both theoretically and experimentally. The investigation is consisted of two steps. First step is to analyze the noise of joints using a hardware and software. The hardware is a part of noise sensors. The second step; according to experimental results, some neural networks are employed for finding robust neural noise analyzer. Five types of neural networks are used to compare each other. From the results, it is noted that the proposed RBFNN gives the best results for analyzing joint noise of the robot manipulator. 相似文献
13.
Multiobjective evolutionary clustering of Web user sessions: a case study in Web page recommendation
G. Nildem Demir A. Şima Uyar Şule Gündüz-Öğüdücü 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2010,14(6):579-597
In this study, we experiment with several multiobjective evolutionary algorithms to determine a suitable approach for clustering
Web user sessions, which consist of sequences of Web pages visited by the users. Our experimental results show that the multiobjective
evolutionary algorithm-based approaches are successful for sequence clustering. We look at a commonly used cluster validity
index to verify our findings. The results for this index indicate that the clustering solutions are of high quality. As a
case study, the obtained clusters are then used in a Web recommender system for representing usage patterns. As a result of
the experiments, we see that these approaches can successfully be applied for generating clustering solutions that lead to
a high recommendation accuracy in the recommender model we used in this paper. 相似文献
14.
Dan Selişteanu Monica Roman Dorin Şendrescu 《Simulation Modelling Practice and Theory》2010,18(9):1297-1313
This paper deals with the problem of modelling and on-line estimation of kinetics for a biomethanation process. This bioprocess is in fact a wastewater biodegradation process with production of methane gas, which takes place inside a Continuous Stirred Tank Bioreactor. The reaction scheme and the analysis of biochemical phenomena inside the bioreactor are used in order to obtain a nonlinear dynamic model of the bioprocess, by means of the pseudo Bond Graph method. Two nonlinear estimation strategies are developed for the identification of unknown kinetics of the bioprocess. First, an estimator is developed by using a state observer based technique. Second, an observer based on high-gain approach is designed and implemented. Several numerical simulations are performed in order to analyse and compare the behaviour and the performance of the proposed estimators. 相似文献
15.
Tarık Çakar 《Journal of Intelligent Manufacturing》2011,22(4):481-490
A neuro-dominance rule (NDR) for single machine total weighted tardiness problem with unequal release date is presented by
the author. To obtain the NDR, backpropagation artificial neural network (BPANN) has been trained using 10,000 data and also
tested using 10,000 another data. Inputs of the trained BPANN are starting date of the first job (t), processing times (pi and pj), due dates (di and dj), weights of the jobs (wi and wj) and ri and rj release dates of the jobs. Output of the BPANN is a decision of which job should precede. Training set and test set have
been obtained using Adjusted Pairwise Interchange method. The proposed NDR provides a sufficient condition for local optimality.
It has been proved that if any sequence violates the NDR then violating jobs are switched according to the total weighted
tardiness criterion. The proposed NDR is compared to a number of competing heuristics (ATC, COVERT, EDD, SPT, LPT, WDD, WSPT,
WPD, CR, FCFS) and meta heuristics (simulated annealing and genetic algorithms) for a set of randomly generated problems.
The problem sizes have been taken as 50, 70, 100. NDR is applied 270,000 randomly generated problems. Computational results
indicate that the NDR dominates the heuristics and meta heuristics in all runs. Therefore, the NDR can improve the upper and
lower bounding schemes. 相似文献
16.
This paper proposes the Mobility-Aware Resource Reservation Protocol (MARSVP) in which mobility and QoS signaling are performed as a single functional block. The key concept of MARSVP is to convey mobility-specific information (binding updates and their associated acknowledgments) by using newly defined RSVP objects embedded in existing RSVP messages. An appealing feature of MARSVP is that it adheres to the current RSVP standard (RFC 2205) and thus requires minimal changes to end nodes without affecting any of the conventional RSVP routers in between. The proposed mechanism is evaluated using a simulation model for application-level performance and an analytical model for network-level signaling cost. Simulation results indicate a 27.9% improvement in QoS interruption when using Mobile IPv6 (MIPv6), 12.5% when using Hierarchical Mobile IPv6 (HMIPv6), and no improvement when using Fast Handovers for MIPv6 (FMIPv6). On the network-level, signaling cost savings of 9.4% and 11.9% are achieved for MIPv6 and HMIPv6, respectively, while FMIPv6 achieves savings of 17.9% when using Voice-over-IP traffic and 26.7% for Video-over-IP traffic. The results of the conducted studies indicate MARSVP’s superiority to conventional RSVP when deployed over wireless networks. 相似文献
17.
In this study, a hybrid intelligent solution system including neural networks, genetic algorithms and simulated annealing has been proposed for the inverse kinematics solution of robotic manipulators. The main purpose of the proposed system is to decrease the end effector error of a neural network based inverse kinematics solution. In the designed hybrid intelligent system, simulated annealing algorithm has been used as a genetic operator to decrease the process time of the genetic algorithm to find the optimum solution. Obtained best solution from the neural network has been included in the initial solution of genetic algorithm with randomly produced solutions. The end effector error has been reduced micrometer levels after the implementation of the hybrid intelligent solution system. 相似文献
18.
Ali Şaman Tosun 《Distributed and Parallel Databases》2006,19(2-3):107-124
Declustering is a common technique used to reduce query response times. Data is declustered over multiple disks and query
retrieval can be parallelized. Most of the research on declustering is targeted at spatial range queries and investigates
schemes with low additive error. Recently, declustering using replication has been proposed to reduce the additive overhead.
Replication significantly reduces retrieval cost of arbitrary queries. In this paper, we propose a disk allocation and retrieval
mechanism for arbitrary queries based on design theory. Using the proposed c-copy replicated declustering scheme,
buckets can be retrieved using at most k disk accesses. Retrieval algorithm is very efficient and is asymptotically optimal with
complexity for a query Q. In addition to the deterministic worst-case bound and efficient retrieval, proposed algorithm handles nonuniform data, high
dimensions, supports incremental declustering and has good fault-tolerance property. Experimental results show the feasibility
of the algorithm.
Recommended by: Sunil Prabhakar 相似文献
19.
The main purpose of this study was to investigate the views of primary students about interactive whiteboard [IWB] use in their classes from attitudinal and pedagogical perspectives. Research was designed as an empirical approach to phenomenology. Data was collected from fifty primary students (fourth to eighth) through focus group interviews. Nvivo 9 qualitative data analysis software was used to analyze data. Results showed that students like instruction with IWB especially for such reasons/capabilities as practical and economical use, better visual presentation, and test-based use. Students were predominantly uncomfortable with the technical problems. They believed that instruction with IWB positively impacted their learning especially because of visualization and contextualization, effective presentation, test-based use, and motivational factors. Finally it was inferred that IWBs were not used to their full potential, and both technical problems and common practices indicated that teachers were still at an initial stage of transmission to instruction with IWB and they needed both technical and pedagogical training. 相似文献
20.
The Tigris is one of the most important transboundary rivers in western Asia and originates in the Toros mountains of the Eastern Anatolia region of Turkey. Multivariate statistical techniques, such as cluster analysis (CA), principal component analysis (PCA) and factor analysis (FA), were applied for the evaluation of temporal/spatial variations and the interpretation of a water quality data set for the Tigris River, which was obtained during 1 year of monitoring. This study presents the usefulness of multivariate statistical techniques for the evaluation and interpretation of complex water quality data sets and apportionment of pollution sources/factors to obtain better information about water quality and the design of a monitoring network for the effective management of water resources. Hierarchical CA grouped 12 months into two periods (the first and second periods) and classified seven monitoring sites into three groups, that is, less polluted sites, medium polluted sites and highly polluted sites, based on similarities in the water quality characteristics. PCA/FA identified five factors in the data structure, which explained 77.5% of the total variance of the data set. This allowed us to group the selected parameters according to common features and to evaluate the influence of each group on the overall variation in water quality. Varifactors obtained from the factor analysis indicated that the parameters responsible for water quality variation were mainly related to soluble salts (natural), organic pollution and nutrients (anthropogenic). Copyright © 2011 John Wiley & Sons, Ltd. 相似文献