全文获取类型
收费全文 | 4330篇 |
免费 | 482篇 |
国内免费 | 48篇 |
专业分类
电工技术 | 53篇 |
综合类 | 47篇 |
化学工业 | 1179篇 |
金属工艺 | 164篇 |
机械仪表 | 261篇 |
建筑科学 | 143篇 |
矿业工程 | 28篇 |
能源动力 | 206篇 |
轻工业 | 359篇 |
水利工程 | 31篇 |
石油天然气 | 30篇 |
无线电 | 748篇 |
一般工业技术 | 1015篇 |
冶金工业 | 144篇 |
原子能技术 | 65篇 |
自动化技术 | 387篇 |
出版年
2024年 | 5篇 |
2023年 | 66篇 |
2022年 | 101篇 |
2021年 | 164篇 |
2020年 | 126篇 |
2019年 | 149篇 |
2018年 | 186篇 |
2017年 | 159篇 |
2016年 | 175篇 |
2015年 | 170篇 |
2014年 | 246篇 |
2013年 | 315篇 |
2012年 | 344篇 |
2011年 | 375篇 |
2010年 | 271篇 |
2009年 | 268篇 |
2008年 | 303篇 |
2007年 | 176篇 |
2006年 | 142篇 |
2005年 | 141篇 |
2004年 | 148篇 |
2003年 | 146篇 |
2002年 | 147篇 |
2001年 | 117篇 |
2000年 | 72篇 |
1999年 | 68篇 |
1998年 | 65篇 |
1997年 | 42篇 |
1996年 | 28篇 |
1995年 | 24篇 |
1994年 | 22篇 |
1993年 | 11篇 |
1992年 | 10篇 |
1991年 | 5篇 |
1990年 | 11篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1973年 | 2篇 |
1966年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有4860条查询结果,搜索用时 0 毫秒
91.
Myung Hyun Lee Hyoung-Ki Choi Kiwan Bang Seokwon 《International Journal of Control, Automation and Systems》2010,8(3):667-676
The odometry information used in mobile robot localization can contain a significant number of errors when robot experiences
slippage. To offset the presence of these errors, the use of a low-cost gyroscope in conjunction with Kalman filtering methods
has been considered by many researchers. However, results from conventional Kalman filtering methods that use a gyroscope
with odometry can unfeasible because the parameters are estimated regardless of the physical constraints of the robot. In
this paper, a novel constrained Kalman filtering method is proposed that estimates the parameters under the physical constraints
using a general constrained optimization technique. The state observability is improved by additional state variables and
the accuracy is also improved through the use of a nonapproximated Kalman filter design. Experimental results show that the
proposed method effectively offsets the localization error while yielding feasible parameter estimation. 相似文献
92.
Usage of frequency based error correction methods for repetitive disturbances becomes popular in data storage devices that use a rotating mechanical power plant. Two distinct disturbance cancellation methods, disturbance observer (DOB) and adaptive feed forward control (AFC) are the most popular approaches used for current drive servo integration. DOB reduces error using a predetermined function that is calculated thorough a complicated process. Generally the response to disturbance and initiation of control action of DOB is relatively fast even if the amount of error reduction is limited. Meanwhile the error elimination capability of AFC for the repetitive disturbance is normally better than DOB as it utilizes a Fourier coefficients updating feature that supports an enhanced fine adaptation of a certain frequency disturbance. Of course, AFC suffers for disturbances that have neighboring close frequencies due to the inherent fundamental frequency dependencies of AFC formulation. In the present work, an attempt for combining benefits of AFC and DOB is made. This might enables control action not only to generate fast response to disturbance but also perform an accurate error rejection. This feature also provides to the closed loop system a frequency selection for enabling a strategic selective error rejection. The proposed method named Hybrid Disturbance Observer (HDOB) is compared to the traditional AFC and DOB. 相似文献
93.
A novel method for automatically constructing taxonomies for specific research domains is presented. The proposed methodology uses term co-occurrence frequencies as an indicator of the semantic closeness between terms. To support the automated creation of taxonomies or subject classifications we present a simple modification to the basic distance measure, and describe a set of procedures by which these measures may be converted into estimates of the desired taxonomy. To demonstrate the viability of this approach, a pilot study on renewable energy technologies is conducted, where the proposed method is used to construct a hierarchy of terms related to alternative energy. These techniques have many potential applications, but one activity in which we are particularly interested is the mapping and subsequent prediction of future developments in the technology and research. 相似文献
94.
Browsing the DOM tree of an XML document is an act of following the links among the nodes of the DOM tree to find some desired nodes without any knowledge for search. When the structure of the XML document is not known to a user, browsing is the basic operation performed for referring the contents of the XML document. If the size of the XML document is very large, however, using a general-purpose XML parser for browsing the DOM tree of the XML document to access arbitrary node may suffer from the lack of memory space for constructing the large DOM tree. To alleviate this problem, we suggest a method to browse the DOM tree of a very large XML document by splitting the XML document into n small XML documents and generating sequentially the DOM tree of each of those small n XML documents. For later reference, the information of some nodes accessed from the DOM tree already generated has been also kept using the concept of their virtual nodes. With our suggested approach, the memory space necessary for browsing the DOM tree of a very large XML document is reduced such that it can be managed by a personal computer. 相似文献
95.
In a graph, a vertex is simplicial if its neighborhood is a clique. For an integer k≥1, a graph G=(VG,EG) is the k-simplicial power of a graph H=(VH,EH) (H a root graph of G) if VG is the set of all simplicial vertices of H, and for all distinct vertices x and y in VG, xyEG if and only if the distance in H between x and y is at most k. This concept generalizes k-leaf powers introduced by Nishimura, Ragde and Thilikos which were motivated by the search for underlying phylogenetic trees; k-leaf powers are the k-simplicial powers of trees. Recently, a lot of work has been done on k-leaf powers and their roots as well as on their variants phylogenetic roots and Steiner roots. For k≤5, k-leaf powers can be recognized in linear time, and for k≤4, structural characterizations are known. For k≥6, the recognition and characterization problems of k-leaf powers are still open. Since trees and block graphs (i.e., connected graphs whose blocks are cliques) have very similar metric properties, it is natural to study k-simplicial powers of block graphs. We show that leaf powers of trees and simplicial powers of block graphs are closely related, and we study simplicial powers of other graph classes containing all trees such as ptolemaic graphs and strongly chordal graphs. 相似文献
96.
Seung Jae Lee 《Information Systems Frontiers》2017,19(4):705-715
The tourism industry is intimately related to the development of technology. Currently, technology-integrated “smart tourism” provides convenience and interactivity, and offers personalized services to tourists. However, the use of the technology-mediated audio guides among tourists in cultural heritage sites is not as active as expected. The underutilization of the audio guides in palaces is confirmed by a survey at Gyeongbok-gung palace, and the underlying reasons are examined by interviewing visitors to Chateau de Versailles. This paper analyzes the low usage of audio guides as a case-study, utilizing Cohen’s basic concepts of tour guides, Dann’s tourist motivation theory and the museum ecology of Bell. Consequently, this paper confirms the multifunctional complexity of audio guides, and suggests improvement of them in functionality (user-friendliness, usability, interactivity and social functions) for program developers, and the strategic use of ICT in promotion of palaces as smart tourism destination in cultural heritage management. 相似文献
97.
Stephen G. McGill Seung‐Joon Yi Hak Yi Min Sung Ahn Sanghyun Cho Kevin Liu Daniel Sun Bhoram Lee Heejin Jeong Jinwook Huh Dennis Hong Daniel D. Lee 《野外机器人技术杂志》2017,34(4):775-801
This paper describes Team THOR's approach to human‐in‐the‐loop disaster response robotics for the 2015 DARPA Robotics Challenge (DRC) Finals. Under the duress of unpredictable networking and terrain, fluid operator interactions and dynamic disturbance rejection become major concerns for effective teleoperation. We present a humanoid robot designed to effectively traverse a disaster environment while allowing for a wide range of manipulation abilities. To complement the robot hardware, a hierarchical software foundation implements network strategies that provide real‐time feedback to an operator under restricted bandwidth using layered user interfaces. Our strategy for humanoid locomotion includes a backward‐facing knee configuration paired with specialized toe and heel lifting strategies that allow the robot to traverse difficult surfaces while rejecting external perturbations. With an upper body planner that encodes operator preferences, predictable motion plans are executed in unforeseen circumstances. These plans are critical for manipulation in unknown environments. Our approach was validated during the DRC Finals competition, where Team THOR scored three points in 18 min of operation time, and the results are presented along with an analysis of each task. 相似文献
98.
Cho Dong-Hyun Lee Donghun Bang Hyochoong Kim Hae-Dong 《International Journal of Control, Automation and Systems》2017,15(4):1729-1737
International Journal of Control, Automation and Systems - In this research, a new control law for the trajectory correction maneuver (TCM) is proposed for a spacecraft assumed to be actuated by a... 相似文献
99.
This paper presents a structural application of a shape optimization method based on a Genetic Algorithm (GA). The method
produces a sequence of fixed-distance step-wise movements of the boundary nodes of a finite element model to derive optimal
shapes from an arbitrary initial design space. The GA is used to find the optimal or near-optimal combination of boundary
nodes to be moved for a given step movement. The GA uses both basic and advanced operators. For illustrative purposes, the
method has been applied to structural shape-optimization. The shape-optimization methodology presented allows local optimization,
where only crucial parts of a structure are optimized as well as global shape-optimization which involves finding the optimal
shape of the structure as a whole for a given environment as described by its loading and freedom conditions. Material can
be removed or added to reach the optimal shape. Two examples of structural shape optimization are included showing local and
global optimization through material removal and addition.
Received October 14, 1999 相似文献
100.
Contour matching using epipolar geometry 总被引:15,自引:0,他引:15
Joon Hee Han Jong Seung Park 《IEEE transactions on pattern analysis and machine intelligence》2000,22(4):358-370
Matching features computed in images is an important process in multiview image analysis. When the motion between two images is large, the matching problem becomes very difficult. In this paper, we propose a contour matching algorithm based on geometric constraints. With the assumption that the contours are obtained from images taken from a moving camera with static scenes, we apply the epipolar constraint between two sets of contours and compute the corresponding points on the contours. From the initial epipolar constraints obtained from corner point matching, candidate contours are selected according to the epipolar geometry, contour end point constraints, and contour distance measures. In order to reduce the possibility of false matches, the number of match points on a contour is also used as a selection measure. The initial epipolar constraint is refined from the matched sets of contours. The algorithm can be applied to a pair or two pairs of images. All of the processes are fully automatic and successfully implemented and tested with various real images 相似文献