全文获取类型
收费全文 | 185950篇 |
免费 | 17609篇 |
国内免费 | 10159篇 |
专业分类
电工技术 | 15217篇 |
技术理论 | 9篇 |
综合类 | 19129篇 |
化学工业 | 18156篇 |
金属工艺 | 7543篇 |
机械仪表 | 16544篇 |
建筑科学 | 21195篇 |
矿业工程 | 6962篇 |
能源动力 | 7981篇 |
轻工业 | 14774篇 |
水利工程 | 7663篇 |
石油天然气 | 8688篇 |
武器工业 | 2091篇 |
无线电 | 10963篇 |
一般工业技术 | 17743篇 |
冶金工业 | 7379篇 |
原子能技术 | 2601篇 |
自动化技术 | 29080篇 |
出版年
2024年 | 770篇 |
2023年 | 2268篇 |
2022年 | 4636篇 |
2021年 | 5380篇 |
2020年 | 5724篇 |
2019年 | 4753篇 |
2018年 | 4668篇 |
2017年 | 5703篇 |
2016年 | 6890篇 |
2015年 | 7271篇 |
2014年 | 11880篇 |
2013年 | 11868篇 |
2012年 | 13827篇 |
2011年 | 15194篇 |
2010年 | 10958篇 |
2009年 | 11200篇 |
2008年 | 10565篇 |
2007年 | 12701篇 |
2006年 | 11054篇 |
2005年 | 9299篇 |
2004年 | 7872篇 |
2003年 | 6719篇 |
2002年 | 5425篇 |
2001年 | 4468篇 |
2000年 | 3808篇 |
1999年 | 3123篇 |
1998年 | 2652篇 |
1997年 | 2219篇 |
1996年 | 1811篇 |
1995年 | 1505篇 |
1994年 | 1352篇 |
1993年 | 996篇 |
1992年 | 922篇 |
1991年 | 672篇 |
1990年 | 572篇 |
1989年 | 485篇 |
1988年 | 408篇 |
1987年 | 277篇 |
1986年 | 236篇 |
1985年 | 220篇 |
1984年 | 258篇 |
1983年 | 242篇 |
1982年 | 197篇 |
1981年 | 97篇 |
1980年 | 98篇 |
1979年 | 66篇 |
1978年 | 53篇 |
1977年 | 47篇 |
1976年 | 44篇 |
1959年 | 30篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Several research efforts over the last decade have attempted to explain user acceptance in mandated environments. This research is an attempt in the same direction. It addresses users’ satisfaction in mandated environments to further contribute to our understanding of how we can manage mandated use of information systems (IS) effectively beyond initial adoption. To better explain users’ IS continuance a revised post-acceptance model is proposed and empirically tested using the structural equation modelling technique. The results demonstrate the reliability and validity of the proposed measurement model and further demonstrate that confirmed expectations and ease of use perceptions explain 61% of the users’ satisfaction in this setting. Our findings have important implications for the management of users in mandated environments as well as for further research in the area of mandated use. To that end, we offer directions for future research. 相似文献
992.
Aminollah Mahabadi Hamid Sarbazi-Azad Ebrahim Khodaie Keivan Navi 《The Journal of supercomputing》2008,45(1):1-14
This paper proposes an efficient parallel algorithm for computing Lagrange interpolation on k-ary n-cube networks. This is done using the fact that a k-ary n-cube can be decomposed into n link-disjoint Hamiltonian cycles. Using these n link-disjoint cycles, we interpolate Lagrange polynomial using full bandwidth of the employed network. Communication in the
main phase of the algorithm is based on an all-to-all broadcast algorithm on the n link-disjoint Hamiltonian cycles exploiting all network channels, and thus, resulting in high-efficiency in using network
resources. A performance evaluation of the proposed algorithm reveals an optimum speedup for a typical range of system parameters
used in current state-of-the-art implementations.
相似文献
Hamid Sarbazi-AzadEmail: Email: |
993.
This paper studies connectivity aspects that arise in image operators that process connected components. The focus is on morphological
image analysis (i.e., on increasing image operators) and, in particular, on a robustness property satisfied by certain morphological
filters that is denominated the strong property. The behavior of alternated compositions of openings and closings is investigated
under certain assumptions, particularly connectedness and a connected component preserving condition. It is shown that these
conditions cannot in general guarantee the strong property of certain connected alternated filters because of issues related
to the locality of the filters. As treated in the paper, there have been a series of misunderstandings in the literature concerning
this topic, and it is important to clarify them. The root cause of those problems is discussed, and a solution is indicated.
The class of connected openings and closings used to build connected alternated filters should therefore be defined to avoid
such situations, since the strong property of alternated filters should be a distinctive characteristic of this class.
相似文献
Victor MaojoEmail: |
994.
Mixtures of probabilistic principal component analyzers model high-dimensional nonlinear data by combining local linear models. Each mixture component is specifically designed to extract the local principal orientations in the data. An important issue with this generative model is its sensitivity to data lying off the low-dimensional manifold. In order to address this problem, the mixtures of robust probabilistic principal component analyzers are introduced. They take care of atypical points by means of a long tail distribution, the Student-t. It is shown that the resulting mixture model is an extension of the mixture of Gaussians, suitable for both robust clustering and dimensionality reduction. Finally, we briefly discuss how to construct a robust version of the closely related mixture of factor analyzers. 相似文献
995.
The eigenvector associated with the smallest eigenvalue of the autocorrelation matrix of input signals is called minor component. Minor component analysis (MCA) is a statistical approach for extracting minor component from input signals and has been applied in many fields of signal processing and data analysis. In this letter, we propose a neural networks learning algorithm for estimating adaptively minor component from input signals. Dynamics of the proposed algorithm are analyzed via a deterministic discrete time (DDT) method. Some sufficient conditions are obtained to guarantee convergence of the proposed algorithm. 相似文献
996.
Christopher Rasmussen 《Autonomous Robots》2008,25(3):205-229
We present a vision- and ladar-based approach to autonomous driving on rural and desert roads that has been tested extensively
in a closed-loop system. The vision component uses Gabor wavelet filters for texture analysis to find ruts and tracks from
which the road vanishing point can be inferred via Hough-style voting, yielding a direction estimate for steering control.
The ladar component projects detected obstacles along the road direction onto the plane of the front of the vehicle and tracks
the 1-D obstacle “gap” presumed due to the road to yield a lateral offset estimate. Several image- and state-based tests to
detect failure conditions such as off-road poses (i.e., there is no road to follow) and poor lighting due to sun glare or
distracting shadows are also explained. The system’s efficacy is demonstrated with analysis of diverse logged data including
from the 2005 DARPA Grand Challenge, as well as tests with full control of a vehicle over 15 km of difficult roads at up to
37 km/h with no waypoints.
相似文献
Christopher RasmussenEmail: |
997.
Michael M. Li Brijesh Verma Xiaolong Fan Kevin Tickle 《Neural computing & applications》2008,17(4):391-397
This paper investigates a new method to solve the inverse problem of Rutherford backscattering (RBS) data. The inverse problem
is to determine the sample structure information from measured spectra, which can be defined as a function approximation problem.
We propose using radial basis function (RBF) neural networks to approximate an inverse function. Each RBS spectrum, which
may contain up to 128 data points, is compressed by the principal component analysis, so that the dimensionality of input
data and complexity of the network are reduced significantly. Our theoretical consideration is tested by numerical experiments
with the example of the SiGe thin film sample and corresponding backscattering spectra. A comparison of the RBF method with
multilayer perceptrons reveals that the former has better performance in extracting structural information from spectra. Furthermore,
the proposed method can handle redundancies properly, which are caused by the constraint of output variables. This study is
the first method based on RBF to deal with the inverse RBS data analysis problem. 相似文献
998.
Automatic composition of broadcast sports video 总被引:1,自引:0,他引:1
This study examines an automatic broadcast soccer video composition system. The research is important as the ability to automatically
compose broadcast sports video will not only improve broadcast video generation efficiency, but also provides the possibility
to customize sports video broadcasting. We present a novel approach to the two major issues required in the system’s implementation,
specifically the camera view selection/switching module and the automatic replay generation module. In our implementation,
we use multi-modal framework to perform video content analysis, event and event boundary detection from the raw unedited main/sub-camera
captures. This framework explores the possible cues using mid-level representations to bridge the gap between low-level features
and high-level semantics. The video content analysis results are utilized for camera view selection/switching in the generated
video composition, and the event detection results and mid-level representations are used to generate replays which are automatically
inserted into the broadcast soccer video. Our experimental results are promising and found to be comparable to those generated
by broadcast professionals. 相似文献
999.
Application of artificial neural network for determination of standard time in machining 总被引:1,自引:1,他引:0
Izabela Kutschenreiter-Praszkiewicz 《Journal of Intelligent Manufacturing》2008,19(2):233-240
The purpose of this article is to present the application of neural network for time per unit determination in small lot production
in machining. A set of features considered as input vector and time consumption in manufacturing process was presented and
treated as output of the neural net. A neural network was used as a machining model. Sensitivity analysis was made and proper
topology of neural network was determined. 相似文献
1000.
Statistical process control (SPC) is a conventional means of monitoring software processes and detecting related problems,
where the causes of detected problems can be identified using causal analysis. Determining the actual causes of reported problems
requires significant effort due to the large number of possible causes. This study presents an approach to detect problems
and identify the causes of problems using multivariate SPC. This proposed method can be applied to monitor multiple measures
of software process simultaneously. The measures which are detected as the major impacts to the out-of-control signals can
be used to identify the causes where the partial least squares (PLS) and statistical hypothesis testing are utilized to validate
the identified causes of problems in this study. The main advantage of the proposed approach is that the correlated indices
can be monitored simultaneously to facilitate the causal analysis of a software process.
Ching-Pao Chang is a PhD candidate in Computer Science & Information Engineering at the National Cheng-Kung University, Taiwan. He received his MA from the University of Southern California in 1998 in Computer Science. His current work deals with the software process improvement and defect prevention using machine learning techniques. Chih-Ping Chu is Professor of Software Engineering in Department of Computer Science & Information Engineering at the National Cheng-Kung University (NCKU) in Taiwan. He received his MA in Computer Science from the University of California, Riverside in 1987, and his Doctorate in Computer Science from Louisiana State University in 1991. He is especially interested in parallel computing and software engineering. 相似文献
Chih-Ping ChuEmail: |
Ching-Pao Chang is a PhD candidate in Computer Science & Information Engineering at the National Cheng-Kung University, Taiwan. He received his MA from the University of Southern California in 1998 in Computer Science. His current work deals with the software process improvement and defect prevention using machine learning techniques. Chih-Ping Chu is Professor of Software Engineering in Department of Computer Science & Information Engineering at the National Cheng-Kung University (NCKU) in Taiwan. He received his MA in Computer Science from the University of California, Riverside in 1987, and his Doctorate in Computer Science from Louisiana State University in 1991. He is especially interested in parallel computing and software engineering. 相似文献