全文获取类型
收费全文 | 84308篇 |
免费 | 8764篇 |
国内免费 | 5263篇 |
专业分类
电工技术 | 6258篇 |
技术理论 | 2篇 |
综合类 | 6549篇 |
化学工业 | 12545篇 |
金属工艺 | 5264篇 |
机械仪表 | 5781篇 |
建筑科学 | 6034篇 |
矿业工程 | 3033篇 |
能源动力 | 2251篇 |
轻工业 | 7977篇 |
水利工程 | 2257篇 |
石油天然气 | 3784篇 |
武器工业 | 929篇 |
无线电 | 9645篇 |
一般工业技术 | 9355篇 |
冶金工业 | 4020篇 |
原子能技术 | 1188篇 |
自动化技术 | 11463篇 |
出版年
2024年 | 551篇 |
2023年 | 1640篇 |
2022年 | 3187篇 |
2021年 | 4356篇 |
2020年 | 3210篇 |
2019年 | 2524篇 |
2018年 | 2632篇 |
2017年 | 2818篇 |
2016年 | 2616篇 |
2015年 | 3699篇 |
2014年 | 4562篇 |
2013年 | 5292篇 |
2012年 | 6085篇 |
2011年 | 6490篇 |
2010年 | 5832篇 |
2009年 | 5686篇 |
2008年 | 5670篇 |
2007年 | 5270篇 |
2006年 | 4948篇 |
2005年 | 4048篇 |
2004年 | 2936篇 |
2003年 | 2210篇 |
2002年 | 2144篇 |
2001年 | 1879篇 |
2000年 | 1683篇 |
1999年 | 1262篇 |
1998年 | 886篇 |
1997年 | 760篇 |
1996年 | 668篇 |
1995年 | 560篇 |
1994年 | 439篇 |
1993年 | 309篇 |
1992年 | 252篇 |
1991年 | 219篇 |
1990年 | 184篇 |
1989年 | 173篇 |
1988年 | 111篇 |
1987年 | 99篇 |
1986年 | 64篇 |
1985年 | 52篇 |
1984年 | 39篇 |
1983年 | 39篇 |
1982年 | 34篇 |
1981年 | 36篇 |
1980年 | 39篇 |
1979年 | 28篇 |
1978年 | 15篇 |
1976年 | 18篇 |
1975年 | 11篇 |
1973年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
In this paper, we present a gradient domain image fusion framework based on the Markov Random Field (MRF) fusion model. In this framework, the salient structures of the input images are fused in the gradient domain, then the final fused image is reconstructed by solving a Poisson equation which forces the gradients of the fused image to be close to the fused gradients. To fuse the structures in the gradient domain, an effective MRF-based fusion model is designed based on both the per-pixel fusion rule defined by the local saliency and also the smoothness constraints over the fusion weights, which is optimized by graph cut algorithm. This MRF-based fusion model enables the accurate estimation of region-based fusion weights for the salient objects or structures. We apply this method to the applications of multi-sensor image fusion, including infrared and visible image fusion, multi-focus image fusion and medical image fusion. Extensive experiments and comparisons show that the proposed fusion model is able to better fuse the multi-sensor images and produces high-quality fusion results compared with the other state-of-the-art methods. 相似文献
92.
Because subjective evaluation is not adequate for assessing work in an automatic system, using an objective image fusion performance metric is a common approach to evaluate the quality of different fusion schemes. In this paper, a multi-resolution image fusion metric using visual information fidelity (VIF) is presented to assess fusion performance objectively. This method has four stages: (1) Source and fused images are filtered and divided into blocks. (2) Visual information is evaluated with and without distortion information in each block. (3) The visual information fidelity for fusion (VIFF) of each sub-band is calculated. (4) The overall quality measure is determined by weighting the VIFF of each sub-band. In our experiment, the proposed fusion assessment method is compared with several existing fusion metrics using the subjective test dataset provided by Petrovic. We found that VIFF performs better in terms of both human perception matching and computational complexity. 相似文献
93.
Guang-Song Han Zhi-Hong Guan Xin-Ming Cheng Yonghong Wu Feng Liu 《International Journal of Control, Automation and Systems》2013,11(6):1122-1127
A novel multiconsensus problem is introduced in multiagent systems. The states of multiple agents in each subnetwork asymptotically converge to a consistent value with information exchanges among subnetworks. The multiconsensus problem of second order multiagent systems with directed topologies is studied. Three linear protocols are proposed to solve the multiconsensus problem. Necessary and sufficient conditions are derived based on matrix theory. Simulations are provided to demonstrate the effectiveness of the theoretical results. 相似文献
94.
This paper focuses on the mechanism underlying the overall delay of a real-time video communication system from the time of capture at the encoder to the time of display at the decoder. A detailed analysis is presented to illustrate the delay problem. We then describe a statistically uniform intra-block refresh scheme for very low delay video communication. By scattering intra-blocks uniformly into continuous frames, the overall delay is significantly decreased, and object changes in the scene could be presented to the end user instantly. For comparison, the overall delay and the peak signal-to-noise ratio (PSNR) performance are tested. The experiment results show that an average of approximately 0.1 dB PSNR gain on average is obtained relative to random intra-macroblock refresh algorithm in H.264 JM, and the end-to-end delay performance is significantly improved. 相似文献
95.
96.
研究高动态环境必须实时自适应追踪混合矩阵的变化,快速浮点独立成分分析(Fast-ICA)算法,可以达到快速收敛.依据梯度在线学习算法性能更好,但是它的缺点是收敛慢,并且依赖适当的收敛算子的选择.为解决上述问题,提出了一种依据梯度优化块自适应ICA算法(GBOBA/ICA),包含Fast-ICA和依据梯度在线学习两种算法... 相似文献
97.
计算机应用现状及发展趋势 总被引:1,自引:0,他引:1
韩建伟 《计算机光盘软件与应用》2010,(11)
人类步入信息时代以后,计算机和人类的关系也显得日益密切.人们的生活、生产以及科学研究都离不开计算机.在这个计算机飞速发展的年代,我们应该了解计算机应用的现状以及它的发展趋势. 相似文献
98.
Collapse-free thermal bonding technique for large area microchambers in plastic lab-on-a-chip applications 总被引:1,自引:0,他引:1
Dong Sung Kim Hyun Sup Lee Jungyoup Han Se Hwan Lee Chong H. Ahn Tai Hun Kwon 《Microsystem Technologies》2008,14(2):179-184
Bonding is an essential step to form microchannels or microchambers in lab-on-a-chip applications. In this paper, we present
a novel plastic thermal bonding technique to seal and form large area microchambers (planar characteristic width and length
on the order of 1 mm and characteristic thickness on the order of 10–100 μm) without collapse by introducing a holed pressure
equalizing plate (HPEP) that includes holes of the same size and shape as the microchambers. To demonstrate the proposed technique,
two types of large area microchambers [(1) 20 × 10 mm and 40 μm thick and (2) 12 × 2.5 mm and 120 μm thick] with microchannels
were designed and replicated on plastic substrates by means of hot embossing and injection molding processes with prepared
two nickel mold inserts. The replicated large area microchambers as well as the microchannels in the plastic lab-on-a-chip
were successfully sealed (i.e., no leakage) and formed without any collapse by the proposed thermal bonding technique with
the help of the HPEP. 相似文献
99.
100.