全文获取类型
收费全文 | 39349篇 |
免费 | 5189篇 |
国内免费 | 2927篇 |
专业分类
电工技术 | 1166篇 |
综合类 | 2841篇 |
化学工业 | 8558篇 |
金属工艺 | 1117篇 |
机械仪表 | 1393篇 |
建筑科学 | 634篇 |
矿业工程 | 1270篇 |
能源动力 | 589篇 |
轻工业 | 10566篇 |
水利工程 | 233篇 |
石油天然气 | 1048篇 |
武器工业 | 206篇 |
无线电 | 3332篇 |
一般工业技术 | 1785篇 |
冶金工业 | 1704篇 |
原子能技术 | 717篇 |
自动化技术 | 10306篇 |
出版年
2024年 | 194篇 |
2023年 | 635篇 |
2022年 | 1136篇 |
2021年 | 1455篇 |
2020年 | 1478篇 |
2019年 | 1230篇 |
2018年 | 1145篇 |
2017年 | 1336篇 |
2016年 | 1459篇 |
2015年 | 1690篇 |
2014年 | 2326篇 |
2013年 | 2756篇 |
2012年 | 3812篇 |
2011年 | 3557篇 |
2010年 | 2684篇 |
2009年 | 2699篇 |
2008年 | 2487篇 |
2007年 | 2924篇 |
2006年 | 2533篇 |
2005年 | 1805篇 |
2004年 | 1402篇 |
2003年 | 1202篇 |
2002年 | 995篇 |
2001年 | 757篇 |
2000年 | 684篇 |
1999年 | 556篇 |
1998年 | 416篇 |
1997年 | 388篇 |
1996年 | 284篇 |
1995年 | 250篇 |
1994年 | 172篇 |
1993年 | 161篇 |
1992年 | 157篇 |
1991年 | 114篇 |
1990年 | 110篇 |
1989年 | 77篇 |
1988年 | 52篇 |
1987年 | 56篇 |
1986年 | 39篇 |
1985年 | 43篇 |
1984年 | 41篇 |
1983年 | 31篇 |
1982年 | 26篇 |
1981年 | 28篇 |
1980年 | 25篇 |
1979年 | 12篇 |
1978年 | 11篇 |
1977年 | 8篇 |
1959年 | 6篇 |
1951年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Marion Oswald 《Artificial Life and Robotics》2009,13(2):390-393
We briefly discuss variants of (extended) spiking neural P systems that combine features from the areas of membrane computing
and spiking neurons.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
992.
Jung-Ho Ahn Cheolmin Choi Sooyeong Kwak Kilcheon Kim Hyeran Byun 《Pattern Analysis & Applications》2009,12(2):167-177
In this study, we propose a new integrated computer vision system designed to track multiple human beings and extract their
silhouette with a pan-tilt stereo camera, so that it can assist in gesture and gait recognition in the field of Human–Robot
Interaction (HRI). The proposed system consists of three modules: detection, tracking and silhouette extraction. These modules
are robust to camera movements, and they work interactively in near real-time. Detection was performed by camera ego-motion
compensation and disparity segmentation. For tracking, we present an efficient mean shift-based tracking method in which the
tracking objects are characterized as disparity weighted color histograms. The silhouette was obtained by two-step segmentation.
A trimap was estimated in advance and then effectively incorporated into the graph-cut framework for fine segmentation. The
proposed system was evaluated with respect to ground truth data, and it was shown to detect and track multiple people very
well and also produce high-quality silhouettes.
相似文献
Hyeran ByunEmail: |
993.
Isaac J. Sledge Timothy C. Havens Jacalyn M. Huband James C. Bezdek James M. Keller 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2009,13(12):1125-1142
As humans, we have innate faculties that allow us to efficiently segment groups of objects. Computers, to some degree, can
be programmed with similar categorical capabilities, which stem from exploratory data analysis. Out of the various subsets
of data reasoning, clustering provides insight into the structure and relationships of input samples situated in a number
of distributions. To determine these relationships, many clustering methods rely on one or more human inputs; the most important
being the number of distributions, c, to seek. This work investigates a technique for estimating the number of clusters from a general type of data called relational
data. Several numerical examples are presented to illustrate the effectiveness of the proposed method. 相似文献
994.
Text characters embedded in images represent a rich source of information for content-based indexing and retrieval applications. However, these text characters are difficult to be detected and recognized due to their various sizes, grayscale values, and complex backgrounds. Existing methods cannot handle well those texts with different contrast or embedded in a complex image background. In this paper, a set of sequential algorithms for text extraction and enhancement of image using cellular automata are proposed. The image enhancement includes gray level, contrast manipulation, edge detection, and filtering. First, it applies edge detection and uses a threshold to filter out for low-contrast text and simplify complex background of high-contrast text from binary image. The proposed algorithm is simple and easy to use and requires only a sample texture binary image as an input. It generates textures with perceived quality, better than those proposed by earlier published techniques. The performance of our method is demonstrated by presenting experimental results for a set of text based binary images. The quality of thresholding is assessed using the precision and recall analysis of the resultant text in the binary image. 相似文献
995.
Dake Chen HAN Jiu-qiang 《通讯和计算机》2009,6(10):1-7,22
This paper describes a new scheme for feature extraction from facial images on FPGA. The proposed method is comprised of two stages. The first stage uses the 5/3 DWT to decompose the original face image into LL, LH, HL, and HH wavelet coefficient to reduce the size of the image. In the second stage, PCA is employed to extract the face features from the wavelet coefficients. Here we use the power iteration algorithm to find the eigenvector of the covariance matrix. We present an efficient hardware architecture using combination of parallel processing module and serial processing module. This method can take the benefits of parallel usage advantage of FPGAs and can save hardware resources. Complete hardware implemented on a Stratix II FPGA. The experimental results show that the system works with high processing rate and only 21% of the logic resources an FPGA are consumed by face recognition logic Thus it is very suitable for the low cost implementation of the face recognition system. 相似文献
996.
997.
Kang-Yi Lien Chien-Ju Liu Yi-Chien Lin Pao-Lin Kuo Gwo-Bin Lee 《Microfluidics and nanofluidics》2009,6(4):539-555
This study presents a new magnetic bead-based microfluidic platform, which integrates three major modules for rapid leukocytes
purification, genomic DNA (gDNA) extraction and fast analysis of genetic gene. By utilizing microfluidic technologies and
magnetic beads conjugated with CD15/45 antibodies, leukocytes in a human whole blood sample can be first purified and concentrated, followed by extraction of gDNA
utilizing surface-charge switchable, DNA-specific, magnetic beads in the lysis solution. Then, specific genes associated with
genetic diseases can be amplified by an on-chip polymerase chain reaction (PCR) process automatically. The whole pretreatment
process including the leukocytes purification and gDNA extraction can be performed in an automatic fashion with the incorporation
of the built bio-separators consisting of microcoils array within less than 20 min. The detection of single nucleotide polymorphism
(SNP) genotyping of methylenetetra-hydrofolate reductase (MTHFR) C677T region associated with an increased risk of genetic
diseases was further performed to demonstrate the capability of the proposed system. The extracted gDNA can be transported
into a micro PCR chamber for on-chip fast nucleic acid amplification of detection genes with minimum human intervention. Hence,
the developed system may provide a powerful automated platform for pretreatment of human leukocytes, gDNA extraction and fast
analysis of genetic gene. 相似文献
998.
计算机网络安全问题已经越来越受到人们的重视,而整个网络安全体系又是以有效的身份认证为基础。分析了传统的身份认证技术的缺点,对签名鉴别进行了概述,详细阐述了基于签名鉴别的身份认证技术的基本原理和基本流程,并根据签名鉴别的基本原理,把签名鉴别技术应用到网络身份认证领域,并详细介绍了基于签名鉴别的网络身份认证系统的体系结构和认证原理。 相似文献
999.
基于可信计算的P2P匿名通信系统 总被引:1,自引:0,他引:1
基于P2P的匿名通信网络在保证用户节点匿名的前提下,不能保证匿名节点的可信性,在介绍P2P匿名通信技术的基础上,将可信计算理论引入其中,提出基于可信计算的P2P匿名通信系统;利用可信计算理论中的硬件级可信平台模块和直接匿名证明理论,增加匿名节点可信性认证和监测环节,有效地解决了入网节点安全问题,使得基于P2P的匿名通信系统更加的安全和全面。 相似文献
1000.
在P2P网络中,有大量的web服务,如何准确高效的发现零散分布于世界各地的语义Web服务呢?文章从P2P网络的特点出发,分析了现有的一些研究和方法,在扩展UDDI的基础上,结合目前语义Web服务匹配的多层匹配思想,提出了P2P网络中支持QoS的语义Web服务匹配和发现的有效方法。该方法采用一个四层次的匹配筛选算法,对QoS各层的匹配算法进行了深入讨论,并以相似函数来度量服务提供方与服务请求方的Web服务相似程度。 相似文献