全文获取类型
收费全文 | 2246篇 |
免费 | 134篇 |
国内免费 | 185篇 |
专业分类
电工技术 | 43篇 |
综合类 | 82篇 |
化学工业 | 27篇 |
金属工艺 | 19篇 |
机械仪表 | 81篇 |
建筑科学 | 30篇 |
矿业工程 | 13篇 |
能源动力 | 20篇 |
轻工业 | 39篇 |
水利工程 | 6篇 |
石油天然气 | 3篇 |
无线电 | 173篇 |
一般工业技术 | 66篇 |
冶金工业 | 4篇 |
原子能技术 | 1篇 |
自动化技术 | 1958篇 |
出版年
2024年 | 6篇 |
2023年 | 50篇 |
2022年 | 94篇 |
2021年 | 109篇 |
2020年 | 51篇 |
2019年 | 34篇 |
2018年 | 37篇 |
2017年 | 56篇 |
2016年 | 50篇 |
2015年 | 76篇 |
2014年 | 141篇 |
2013年 | 117篇 |
2012年 | 119篇 |
2011年 | 193篇 |
2010年 | 112篇 |
2009年 | 160篇 |
2008年 | 169篇 |
2007年 | 129篇 |
2006年 | 146篇 |
2005年 | 91篇 |
2004年 | 100篇 |
2003年 | 69篇 |
2002年 | 77篇 |
2001年 | 35篇 |
2000年 | 40篇 |
1999年 | 41篇 |
1998年 | 29篇 |
1997年 | 34篇 |
1996年 | 29篇 |
1995年 | 26篇 |
1994年 | 22篇 |
1993年 | 17篇 |
1992年 | 15篇 |
1991年 | 10篇 |
1990年 | 18篇 |
1989年 | 3篇 |
1988年 | 10篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1954年 | 1篇 |
排序方式: 共有2565条查询结果,搜索用时 31 毫秒
1.
A double optimal projection method that involves projections for intra-cluster and inter-cluster dimensionality reduction are proposed for video fingerprinting. The video is initially set as a graph with frames as its vertices in a high-dimensional space. A similarity measure that can compute the weights of the edges is then proposed. Subsequently, the video frames are partitioned into different clusters based on the graph model. Double optimal projection is used to explore the optimal mapping points in a low-dimensional space to reduce the video dimensions. The statistics and geometrical fingerprints are generated to determine whether a query video is copied from one of the videos in the database. During matching, the video can be roughly matched by utilizing the statistics fingerprint. Further matching is thereafter performed in the corresponding group using geometrical fingerprints. Experimental results show the good performance of the proposed video fingerprinting method in robustness and discrimination. 相似文献
2.
Human skin detection in images is desirable in many practical applications, e.g., human–computer interaction and adult-content filtering. However, existing methods are mainly suffer from confusing backgrounds in real-world images. In this paper, we try to address this issue by exploring and combining several human skin properties, i.e. color property, texture property and region property. First, images are divided into superpixels, and robust skin seeds and background seeds are acquired through color property and texture property of skin. Then we combining color, region and texture properties of skin by proposing a novel skin color and texture based graph cuts (SCTGC) to acquire the final skin detection results. Comprehensive and comparative experiments show that the proposed method achieves promising performance and outperforms many state-of-the-art methods over publicly available challenging datasets with a great part of hard images. 相似文献
3.
大数据时代,Graph500是评测超级计算机处理数据密集型应用能力的重要工具,E级验证系统的图遍历处理能力主要受限于内存空间和访存带宽,尤其是内存空间利用率直接决定了图的测试规模和测试性能.针对天河E级验证系统小内存特征,提出了基于双向位图的大规模图数据压缩存储方法(bidirectional-bitmap based CSR,Bi-CSR),Bi-CSR在CSR矩阵压缩的基础上引入行方向位图和列方向位图协同完成稀疏矩阵压缩存储,行方向位图主要负责行方向位图的压缩存储与索引,列方向位图除了进一步压缩图存储空间,还负责为顶点遍历向量并行优化提供加速空间.Bi-CSR大幅度减少了稀疏矩阵存储空间.面向天河E级验证系统,当图输入规模为237时,Graph500的图存储空间节约效率接近70%,全系统稳定测试性能为2.131E+12TEPS,性能最大加速比超过100倍. 相似文献
4.
《Displays》2021
Recently, the proposal of graph convolutional networks (GCN) has successfully implemented into hyperspectral image data representation and analysis. In spite of the great success, there are still several major challenges in hyperspectral image classification, including within-class diversity, and between-class similarity, which generally degenerate hyperspectral image classification performance. To address the problems, we propose a discriminative graph convolution networks (DGCN) for hyperspectral image classification. This method introduces the concepts of within-class scatter and between-class scatter, which respectively reflect the global geometric structure and discriminative information of the input space. The experimental results on the hyperspectral data sets show that the proposed method has good classification performance. 相似文献
5.
6.
While most of the knowledge bases already support the English language, there is only one knowledge base for the Persian language, known as FarsBase, which is automatically created via semi-structured web information. Unlike English knowledge bases such as Wikidata, which have tremendous community support, the population of a knowledge base like FarsBase must rely on automatically extracted knowledge. Knowledge base population can let FarsBase keep growing in size, as the system continues working. In this paper, we present a knowledge base population system for the Persian language, which extracts knowledge from unlabelled raw text, crawled from the Web. The proposed system consists of a set of state-of-the-art modules such as an entity linking module as well as information and relation extraction modules designed for FarsBase. Moreover, a canonicalization system is introduced to link extracted relations to FarsBase properties. Then, the system uses knowledge fusion techniques with minimal intervention of human experts to integrate and filter the proper knowledge instances, extracted by each module. To evaluate the performance of the presented knowledge base population system, we present the first gold dataset for benchmarking knowledge base population in the Persian language, which consisting of 22015 FarsBase triples and verified by human experts. The evaluation results demonstrate the efficiency of the proposed system. 相似文献
7.
This paper addresses a variant of two-dimensional cutting problems in which rectangular small pieces are obtained by cutting a rectangular object through guillotine cuts. The characteristics of this variant are (i) the object contains some defects, and the items cut must be defective-free; (ii) there is an upper bound on the number of times an item type may appear in the cutting pattern; (iii) the number of guillotine stages is not restricted. This problem commonly arises in industrial settings that deal with defective materials, e.g. either by intrinsic characteristics of the object as in the cutting of wooden boards with knotholes in the wood industry, or by the manufacturing process as in the production of flat glass in the glass industry. We propose a compact integer linear programming (ILP) model for this problem based on the discretisation of the defective object. As solution methods for the problem, we develop a Benders decomposition algorithm and a constraint-programming (CP) based algorithm. We evaluate these approaches through computational experiments, using benchmark instances from the literature. The results show that the methods are effective on different types of instances and can find optimal solutions even for instances with dimensions close to real-size. 相似文献
8.
The rapid growth of data and the requirement of designers to track massive data to obtain design stimuli have posed challenges to conceptual design, thereby promoting the development of data-driven design. Concept networks precisely capture design information from a large volume of unstructured and heterogeneous textual data and saliently decrease time and labor cost for designers to read texts, which creates new opportunities for developing a smart product design system. To advance data-driven design, this study proposes the novel function-structure concept network (FSCN) construction method, which combines sentence parsing and word/phrase extraction to integrate functional and structural information. Furthermore, a network analysis method is proposed to explore design information associations that contain both explicit and implicit associations together and thereby recommend them simultaneously to designers as inspirational stimuli to support design ideation. This approach can enhance designers' capabilities to build associations between design information, conceive new design ideas during conceptual design, and increase creativity for solving design problems. The proposed FSCN construction and analysis method can be used as an auxiliary tool to visualize associations among design information so as to inspire idea generation in the early stage of conceptual design. An illustrative example was used to validate the practicability of the proposed methodology. The code of the proposed method is available at https://github.com/KWflyer/FSCN. 相似文献
9.
空间句法:从图论的角度看中微观城市形态 总被引:2,自引:0,他引:2
如何从整体的角度研究城市形态的复杂性?空间句法在城市形态领域中关注城市形态空间之间的整体联系,运用图论的数学理论和方法建立了城市形态的模型,发现了不同城市具有相似的城市空间拓扑关系,以及特定城市空间之间复杂的整体关联在很大程度上决定了中微观层面的人车流和用地的分布,给城市形态复杂性研究提供了坚实可行的理论基础和方法程序、也给整合交通规划和用地规划的城市规划和设计提供了一种具体的实践角度。本文简要回顾了城市形态研究中关于要素和关联的研究发展、详细解释了空间句法从图论的角度研究城市形态的整体关联,最后分析了空间句法在伯明翰Brindleypalce案例中的应用。 相似文献
10.