全文获取类型
收费全文 | 49698篇 |
免费 | 4410篇 |
国内免费 | 2097篇 |
专业分类
电工技术 | 2838篇 |
技术理论 | 7篇 |
综合类 | 3244篇 |
化学工业 | 8259篇 |
金属工艺 | 2920篇 |
机械仪表 | 3204篇 |
建筑科学 | 3531篇 |
矿业工程 | 1582篇 |
能源动力 | 1531篇 |
轻工业 | 3109篇 |
水利工程 | 776篇 |
石油天然气 | 3138篇 |
武器工业 | 464篇 |
无线电 | 5829篇 |
一般工业技术 | 6363篇 |
冶金工业 | 2418篇 |
原子能技术 | 687篇 |
自动化技术 | 6305篇 |
出版年
2024年 | 113篇 |
2023年 | 877篇 |
2022年 | 1276篇 |
2021年 | 2093篇 |
2020年 | 1612篇 |
2019年 | 1334篇 |
2018年 | 1530篇 |
2017年 | 1768篇 |
2016年 | 1579篇 |
2015年 | 2055篇 |
2014年 | 2652篇 |
2013年 | 3183篇 |
2012年 | 3343篇 |
2011年 | 3594篇 |
2010年 | 3023篇 |
2009年 | 2891篇 |
2008年 | 2883篇 |
2007年 | 2736篇 |
2006年 | 2620篇 |
2005年 | 2239篇 |
2004年 | 1578篇 |
2003年 | 1357篇 |
2002年 | 1355篇 |
2001年 | 1160篇 |
2000年 | 1139篇 |
1999年 | 1144篇 |
1998年 | 957篇 |
1997年 | 810篇 |
1996年 | 754篇 |
1995年 | 582篇 |
1994年 | 493篇 |
1993年 | 330篇 |
1992年 | 264篇 |
1991年 | 195篇 |
1990年 | 171篇 |
1989年 | 134篇 |
1988年 | 111篇 |
1987年 | 57篇 |
1986年 | 56篇 |
1985年 | 34篇 |
1984年 | 28篇 |
1983年 | 23篇 |
1982年 | 24篇 |
1981年 | 14篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1970年 | 2篇 |
1959年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Yue Zhao Jianjian Yue Wei Song Xiaona Xu Xiali Li Licheng Wu Qiang Ji 《计算机、材料和连续体(英文)》2019,60(3):1223-1235
Tibetan language has very limited resource for conventional automatic speech recognition so far. It lacks of enough data, sub-word unit, lexicons and word inventories for some dialects. And speech content recognition and dialect classification have been treated as two independent tasks and modeled respectively in most prior works. But the two tasks are highly correlated. In this paper, we present a multi-task WaveNet model to perform simultaneous Tibetan multi-dialect speech recognition and dialect identification. It avoids processing the pronunciation dictionary and word segmentation for new dialects, while, in the meantime, allows training speech recognition and dialect identification in a single model. The experimental results show our method can simultaneously recognize speech content for different Tibetan dialects and identify the dialect with high accuracy using a unified model. The dialect information used in output for training can improve multi-dialect speech recognition accuracy, and the low-resource dialects got higher speech content recognition rate and dialect classification accuracy by multi-dialect and multi-task recognition model than task-specific models. 相似文献
52.
Pitting corrosion and crevice corrosion of passivated steels were measured by using a double‐mode syringe electrolyte cell built on an environment chamber. The setup, when set in noncontact mode, could measure pitting potentials and critical temperatures, and crevice corrosion potentials if in contact mode. It could be employed to distinguish the pitting and crevice corrosion damage of reinforcing steel in concrete. 相似文献
53.
54.
探究了GB/T 3965—2012《熔敷金属中扩散氢测定方法》中载气热提取法收集条件对测定扩散氢含量的影响,并与水银法进行了对比。研究结果表明,样本炉温设定为400℃,A型试块的内部温度大约在51 min时稳定在358℃左右,B型试块内部温度大约在27 min时稳定在391℃左右;载气热提取法电信号曲线收集结束点的电信号及斜率均接近0时获得的结果与水银法具有较好的一致性。 相似文献
55.
56.
Guoqiang Yu Xiguang Gao Chuyang Xie Yingdong Song 《Fatigue & Fracture of Engineering Materials & Structures》2019,42(2):454-465
Understanding the in‐plane shear behaviour of composites is essential to establish the design basis for practical applications. This study aims to investigate the shear damage behaviours of 2D needled C/SiC composites by various characterization techniques. The effect of layer arrangement on shear modulus and strength was discussed via shear stress‐strain responses. The shear strain field evolution and uniformity variation were studied by digital image correlation. It shows that the uniformity of shear strain field changes with the shear load, and the shear strain field evolution consist of 5 stages. The electrical resistivity measurement results indicate that structural deformation and damage evolution caused the electrical resistivity change. Furthermore, the damage evolution has a double effect on the electrical resistivity variation. The acoustic emission monitoring shows that the shear damage evolution is a 3‐stage nonlinear process before failure. The shear damages were categorized via acoustic characteristics. Besides, the postfailure behaviours were also discussed in this study. 相似文献
57.
Limei Song Jianhua Gao Minmin Liang Xiaojun Li Jiangtao Li Liuchang Wang 《中国稀土学报(英文版)》2019,37(3):232-236
In this work, CaF_2:Ln~(3+)(Ln:Er,Er/Yb)/Nafion composite films were prepared using Nafion as modifications and matrices by dripping method. The composite films were characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD) and scanning electron microscopy(SEM). Composite films are transparent and CaF_2:Ln~(3+)(Ln:Er,Er/Yb) nanoparticles are well dispersed in Nafion films.The thicknesses of CaF_2:Er~(3+)/Nafion and CaF_2:Er~(3+),Yb~(3+)/Nafion composite film are about 77 and 73 μm,respectively. The nanoparticles in composite film possess cubic phase. CaF_2:Er~(3+),Yb~(3+)/Nafion composite film has stronger characteristic emission of Er~(3+) around 1530 nm with full width at half-maximum(FWHM) of 73 nm and longer luminescence lifetimes of 22.04 μs(25.03%) and 100.77 μs(74.97%). 相似文献
58.
59.
60.
Jeong Ji-Seong Song Min-Ho Lee Sang-Ho Kim Mihye Baek Nakhoon Yoo Kwan-Hee 《The Journal of supercomputing》2019,75(8):4505-4518
The Journal of Supercomputing - This paper presents a web-based three-dimensional (3D) navigation system for a spinal disease ontology using a 3D virtual human spine. The 3D navigation system... 相似文献