全文获取类型
收费全文 | 20247篇 |
免费 | 3726篇 |
国内免费 | 2524篇 |
专业分类
电工技术 | 1007篇 |
综合类 | 2107篇 |
化学工业 | 975篇 |
金属工艺 | 356篇 |
机械仪表 | 1218篇 |
建筑科学 | 251篇 |
矿业工程 | 216篇 |
能源动力 | 91篇 |
轻工业 | 340篇 |
水利工程 | 104篇 |
石油天然气 | 384篇 |
武器工业 | 283篇 |
无线电 | 4081篇 |
一般工业技术 | 1193篇 |
冶金工业 | 897篇 |
原子能技术 | 41篇 |
自动化技术 | 12953篇 |
出版年
2024年 | 118篇 |
2023年 | 407篇 |
2022年 | 874篇 |
2021年 | 997篇 |
2020年 | 976篇 |
2019年 | 699篇 |
2018年 | 583篇 |
2017年 | 722篇 |
2016年 | 822篇 |
2015年 | 891篇 |
2014年 | 1292篇 |
2013年 | 1157篇 |
2012年 | 1473篇 |
2011年 | 1604篇 |
2010年 | 1314篇 |
2009年 | 1366篇 |
2008年 | 1410篇 |
2007年 | 1542篇 |
2006年 | 1355篇 |
2005年 | 1154篇 |
2004年 | 947篇 |
2003年 | 876篇 |
2002年 | 716篇 |
2001年 | 490篇 |
2000年 | 419篇 |
1999年 | 380篇 |
1998年 | 314篇 |
1997年 | 242篇 |
1996年 | 187篇 |
1995年 | 174篇 |
1994年 | 137篇 |
1993年 | 134篇 |
1992年 | 110篇 |
1991年 | 52篇 |
1990年 | 48篇 |
1989年 | 69篇 |
1988年 | 42篇 |
1987年 | 25篇 |
1986年 | 23篇 |
1985年 | 34篇 |
1984年 | 33篇 |
1983年 | 44篇 |
1982年 | 38篇 |
1981年 | 33篇 |
1980年 | 27篇 |
1979年 | 22篇 |
1978年 | 23篇 |
1977年 | 26篇 |
1976年 | 23篇 |
1974年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
TextonBoost for Image Understanding: Multi-Class Object Recognition and Segmentation by Jointly Modeling Texture,Layout, and Context 总被引:5,自引:0,他引:5
Jamie Shotton John Winn Carsten Rother Antonio Criminisi 《International Journal of Computer Vision》2009,81(1):2-23
This paper details a new approach for learning a discriminative model of object classes, incorporating texture, layout, and
context information efficiently. The learned model is used for automatic visual understanding and semantic segmentation of
photographs. Our discriminative model exploits texture-layout filters, novel features based on textons, which jointly model patterns of texture and their spatial layout. Unary classification
and feature selection is achieved using shared boosting to give an efficient classifier which can be applied to a large number
of classes. Accurate image segmentation is achieved by incorporating the unary classifier in a conditional random field, which
(i) captures the spatial interactions between class labels of neighboring pixels, and (ii) improves the segmentation of specific
object instances. Efficient training of the model on large datasets is achieved by exploiting both random feature selection
and piecewise training methods.
High classification and segmentation accuracy is demonstrated on four varied databases: (i) the MSRC 21-class database containing
photographs of real objects viewed under general lighting conditions, poses and viewpoints, (ii) the 7-class Corel subset
and (iii) the 7-class Sowerby database used in He et al. (Proceeding of IEEE Conference on Computer Vision and Pattern Recognition,
vol. 2, pp. 695–702, June 2004), and (iv) a set of video sequences of television shows. The proposed algorithm gives competitive and visually pleasing results
for objects that are highly textured (grass, trees, etc.), highly structured (cars, faces, bicycles, airplanes, etc.), and
even articulated (body, cow, etc.).
J. Shotton is now working at Toshiba Corporate Research & Development Center, Kawasaki, Japan. 相似文献
992.
Shiro Kumano Kazuhiro Otsuka Junji Yamato Eisaku Maeda Yoichi Sato 《International Journal of Computer Vision》2009,83(2):178-194
In this paper, we propose a method for pose-invariant facial expression recognition from monocular video sequences. The advantage
of our method is that, unlike existing methods, our method uses a simple model, called the variable-intensity template, for
describing different facial expressions. This makes it possible to prepare a model for each person with very little time and
effort. Variable-intensity templates describe how the intensities of multiple points, defined in the vicinity of facial parts,
vary with different facial expressions. By using this model in the framework of a particle filter, our method is capable of
estimating facial poses and expressions simultaneously. Experiments demonstrate the effectiveness of our method. A recognition
rate of over 90% is achieved for all facial orientations, horizontal, vertical, and in-plane, in the range of ±40 degrees,
±20 degrees, and ±40 degrees from the frontal view, respectively.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
993.
Mehrtash T. Harandi Majid Nili Ahmadabadi Babak N. Araabi 《International Journal of Computer Vision》2009,81(2):191-204
This paper presents a novel learning approach for Face Recognition by introducing Optimal Local Basis. Optimal local bases
are a set of basis derived by reinforcement learning to represent the face space locally. The reinforcement signal is designed
to be correlated to the recognition accuracy. The optimal local bases are derived then by finding the most discriminant features
for different parts of the face space, which represents either different individuals or different expressions, orientations,
poses, illuminations, and other variants of the same individual. Therefore, unlike most of the existing approaches that solve
the recognition problem by using a single basis for all individuals, our proposed method benefits from local information by
incorporating different bases for its decision. We also introduce a novel classification scheme that uses reinforcement signal
to build a similarity measure in a non-metric space.
Experiments on AR, PIE, ORL and YALE databases indicate that the proposed method facilitates robust face recognition under
pose, illumination and expression variations. The performance of our method is compared with that of Eigenface, Fisherface,
Subclass Discriminant Analysis, and Random Subspace LDA methods as well. 相似文献
994.
Maria-Jose Escobar Guillaume S. Masson Thierry Vieville Pierre Kornprobst 《International Journal of Computer Vision》2009,82(3):284-301
We propose a bio-inspired feedforward spiking network modeling two brain areas dedicated to motion (V1 and MT), and we show
how the spiking output can be exploited in a computer vision application: action recognition. In order to analyze spike trains,
we consider two characteristics of the neural code: mean firing rate of each neuron and synchrony between neurons. Interestingly,
we show that they carry some relevant information for the action recognition application. We compare our results to Jhuang
et al. (Proceedings of the 11th international conference on computer vision, pp. 1–8, 2007) on the Weizmann database. As a conclusion, we are convinced that spiking networks represent a powerful alternative framework
for real vision applications that will benefit from recent advances in computational neuroscience. 相似文献
995.
Median MSD-based method for face recognition 总被引:2,自引:0,他引:2
An improved maximum scatter difference (MSD) criterion is proposed in this paper. A weakness of existing MSD model is that the class mean vector in the expressions of within-class scatter matrix and between-class scatter matrix is estimated by class sample average. Under the non-ideal conditions such as variations of expression, illumination, pose, and so on, there will be some outliers in the sample set, so the class sample average is not sufficient to provide an accurate estimate of the class mean using a few of given samples. As a result, the recognition performance of traditional MSD model will decrease. To address this problem, also to render MSD model rather robust, within-class median vector rather than within-class mean vector is used in the original MSD method. The results of experiments conducted on CAS-PEAL and FERET face database indicate the effectiveness of the proposed approach. 相似文献
996.
Several authors have hailed intuition as one of the defining features of expertise. In particular, while disagreeing on almost
anything that touches on human cognition and artificial intelligence, Hubert Dreyfus and Herbert Simon agreed on this point.
However, the highly influential theories of intuition they proposed differed in major ways, especially with respect to the
role given to search and as to whether intuition is holistic or analytic. Both theories suffer from empirical weaknesses.
In this paper, we show how, with some additions, a recent theory of expert memory (the template theory) offers a coherent
and wide-ranging explanation of intuition in expert behaviour. It is shown that the theory accounts for the key features of
intuition: it explains the rapid onset of intuition and its perceptual nature, provides mechanisms for learning, incorporates
processes showing how perception is linked to action and emotion, and how experts capture the entirety of a situation. In
doing so, the new theory addresses the issues problematic for Dreyfus’s and Simon’s theories. Implications for research and
practice are discussed.
相似文献
Fernand GobetEmail: |
997.
This work proposes a method to decompose the kernel within-class eigenspace into two subspaces: a reliable subspace spanned
mainly by the facial variation and an unreliable subspace due to limited number of training samples. A weighting function
is proposed to circumvent undue scaling of eigenvectors corresponding to the unreliable small and zero eigenvalues. Eigenfeatures
are then extracted by the discriminant evaluation in the whole kernel space. These efforts facilitate a discriminative and
stable low-dimensional feature representation of the face image. Experimental results on FERET, ORL and GT databases show
that our approach consistently outperforms other kernel based face recognition methods.
相似文献
Alex KotEmail: |
998.
In this paper, we study the performance improvement that it is possible to obtain combining classifiers based on different
notions (each trained using a different physicochemical property of amino-acids). This multi-classifier has been tested in
three problems: HIV-protease; recognition of T-cell epitopes; predictive vaccinology. We propose a multi-classifier that combines
a classifier that approaches the problem as a two-class pattern recognition problem and a method based on a one-class classifier.
Several classifiers combined with the “sum rule” enables us to obtain an improvement performance over the best results previously
published in the literature.
相似文献
Loris NanniEmail: |
999.
Control chart patterns (CCPs) are widely used to identify the potential process problems in modern manufacturing industries.
The earliest statistical techniques, including chart and R chart, are respectively used for monitoring process mean and process variance. Recently, pattern recognition techniques based
on artificial neural network (ANN) are very popular to be applied to recognize unnatural CCPs. However, most of them are limited
to recognize simple CCPs arising from single type of unnatural variation. In other words, they are incapable to handle the
problem of concurrent CCPs where two types of unnatural variation exist together within the manufacturing process. To facilitate
the research gap, this paper presents a hybrid approach based on independent component analysis (ICA) and decision tree (DT)
to identify concurrent CCPs. Without loss of generality, six types of concurrent CCPs are used to validate the proposed method.
Experimental results show that the proposed approach is very successful to handle most of the concurrent CCPs. The proposed
method has two limitations in real application: it needs at least two concurrent CCPs to reconstruct their source patterns
and it may be incapable to handle the concurrent pattern incurred by two correlated process (“upward trend” and “upward shift”). 相似文献
1000.