全文获取类型
收费全文 | 15298篇 |
免费 | 1859篇 |
国内免费 | 1125篇 |
专业分类
电工技术 | 3004篇 |
技术理论 | 9篇 |
综合类 | 1691篇 |
化学工业 | 670篇 |
金属工艺 | 278篇 |
机械仪表 | 1456篇 |
建筑科学 | 1032篇 |
矿业工程 | 661篇 |
能源动力 | 218篇 |
轻工业 | 358篇 |
水利工程 | 221篇 |
石油天然气 | 290篇 |
武器工业 | 168篇 |
无线电 | 2146篇 |
一般工业技术 | 803篇 |
冶金工业 | 350篇 |
原子能技术 | 19篇 |
自动化技术 | 4908篇 |
出版年
2024年 | 142篇 |
2023年 | 353篇 |
2022年 | 674篇 |
2021年 | 849篇 |
2020年 | 815篇 |
2019年 | 416篇 |
2018年 | 377篇 |
2017年 | 463篇 |
2016年 | 471篇 |
2015年 | 534篇 |
2014年 | 1150篇 |
2013年 | 867篇 |
2012年 | 1307篇 |
2011年 | 1147篇 |
2010年 | 881篇 |
2009年 | 767篇 |
2008年 | 830篇 |
2007年 | 1032篇 |
2006年 | 799篇 |
2005年 | 781篇 |
2004年 | 650篇 |
2003年 | 568篇 |
2002年 | 493篇 |
2001年 | 460篇 |
2000年 | 358篇 |
1999年 | 263篇 |
1998年 | 174篇 |
1997年 | 148篇 |
1996年 | 96篇 |
1995年 | 92篇 |
1994年 | 78篇 |
1993年 | 69篇 |
1992年 | 44篇 |
1991年 | 37篇 |
1990年 | 31篇 |
1989年 | 16篇 |
1988年 | 9篇 |
1987年 | 11篇 |
1986年 | 9篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
In this paper, the authors address the problem of edge-perception for its applications to vision-feedback control in robotic systems.In natural vision, the recognition of objects takes place through the process consisting of eye system, neural networks and cognition. The cognitive process, in turn yields a phenomenon known as perception. This is the phenomenon of perception of physical attributes, such as edges, color and texture, etc., which is responsible for the recognition of objects through the natural vision processes.In this paper, we make an attempt to postulate the theory of perception for gray-level images. The gray-level images, when going through the cognitive and perception processes, are contaminated by the uncertainty; here we call it cognitive uncertainty.The studies in this paper are confined to the phenomenon of edge-perception for two-dimensional gray-level images, however, these studies can be extended to other types of visual attributes both in two-dimensional and three-dimensional spaces. Indeed, the perception of these attributes, which attempts to emulate the human vision system, may help in the design of a truly robust computer vision-feedback control system for robotic applications. 相似文献
62.
63.
为提高舌控智能辅助系统舌部运动信息的采集精度,利用STM32H743和LabVIEW设计了一种对舌机接口辅助系统进行信号采集、传输的通信装置.该装置通过舌部触碰嵌入式电极传感器发出信号并传输给单片机(进行舌控信号采集),然后通过串口传给上位机以此最终实现数据的采集与保存.实验结果表明,该装置可有效完成舌控智能辅助系统对控制信号的采集与传输,并具有实时显示、自动保存和查询历史数据等功能; 因此,该装置在舌控智能辅助系统的信号采集中具有良好的应用前景. 相似文献
64.
基于边缘提取的图像拼接 总被引:1,自引:1,他引:0
对车牌识别系统中的图像拼接问题进行了研究,提出了一种基于边缘提取的图像拼接算法.实验结果证明,该算法获得了理想的拼接效果. 相似文献
65.
66.
Fiber-based hygroresponsive torsional actuators provide desirable merits, such as light weight and shapeability, for developing smart systems to harvest energy from moisture which is a ubiquitous natural resource. A key challenge in this development is to realize moisture-triggered actuation combining large actuation and rapid responses. Here, a multiscale design strategy is explored to create high-performance hygroresponsive torsional actuators consisting of chitosan and multiwalled carbon nanotubes (MWCNTs). The superior actuation performance arises from the synergism of contributing factors at different scales, including 1) MWNCTs accelerate the water transport in primary twisted fibers (PTFs), fostering the rotation of PTFs upon moisture stimuli; 2) in situ-formed hierarchically-assembled twists realize cascade amplification of moisture-triggered actuation. Specifically, PTFs are self-twisted to generate secondary helical yarns, that are subsequently over-twisted to yield tertiary coiled yarn. The resultant yarn actuator can reach a maximum rotation speed of 11 400 rpm in 5 s, output gravitational potential energy of 2.4 J kg−1 and gravitational potential power of 0.053 W kg−1 during contraction. This work represents the first design of fiber-based actuators by virtue of moisture-triggered in situ formation of yarns. The established principles of multiscale design will enable high-performance fiber-based hygroresponsive actuators toward advanced intelligent textile and soft robotics. 相似文献
67.
弧焊逆变电源的发展趋势分析 总被引:3,自引:1,他引:3
本文针对弧焊逆变电源中的几个关键问题,如功率开关器件的性能特点,增大输出变压器的功率,逆变电源的智能控制等,评述了当前的技术水平及今后的发展趋势。 相似文献
68.
A surfactant‐free method to produce responsive polymer microgels is introduced. As an example, poly(methacrylic acid) hydrogels with varying crosslinking density have been synthesized in bulk and then chopped using a high shear mechanical cutter to form microgel particles dispersed in water. The mechanical cutting technique enables the concentration and particle size distribution of the microgel suspensions to be easily controlled, therefore making the rheology of the suspensions tuneable. The particle size distribution of the dispersions, characterized using light scattering, was dependent on the speed and duration of mechanical cutting. The particle size distribution also depended on the degree of crosslinking of the hydrogel. The higher the crosslinking density, the lower the average mean diameter of the resulting microgel particles. The lower the crosslinking density of the hydrogel, the larger the difference between the maximum and minimum particle size. The time to complete swelling of the particles upon change in pH was measured to be up to 45 s, depending on the particle size. The rheology of the resulting suspensions as a function of pH was investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 104: 1912–1919, 2007 相似文献
69.
70.
文章介绍了PIT Navigator对水泥熟料生产自动化控制的实现,基于神经网络的自学习、自适应控制元件,将相关的过程数据记录下来,随后借助数据关联性进行分析,在预测和自学习过程模型(模型预测控制)中处理这些数据,并计算过程参数的实时预测,使用这些工具,可以实现更稳定的窑况,同时提高产量和降低能耗。 相似文献