全文获取类型
收费全文 | 119868篇 |
免费 | 12839篇 |
国内免费 | 6272篇 |
专业分类
电工技术 | 9047篇 |
技术理论 | 12篇 |
综合类 | 8679篇 |
化学工业 | 18324篇 |
金属工艺 | 7291篇 |
机械仪表 | 7902篇 |
建筑科学 | 9635篇 |
矿业工程 | 4070篇 |
能源动力 | 3679篇 |
轻工业 | 8055篇 |
水利工程 | 2753篇 |
石油天然气 | 6132篇 |
武器工业 | 1339篇 |
无线电 | 13964篇 |
一般工业技术 | 13721篇 |
冶金工业 | 5428篇 |
原子能技术 | 1677篇 |
自动化技术 | 17271篇 |
出版年
2024年 | 624篇 |
2023年 | 2231篇 |
2022年 | 4394篇 |
2021年 | 5881篇 |
2020年 | 4421篇 |
2019年 | 3571篇 |
2018年 | 4053篇 |
2017年 | 4411篇 |
2016年 | 4076篇 |
2015年 | 5575篇 |
2014年 | 6805篇 |
2013年 | 7965篇 |
2012年 | 9020篇 |
2011年 | 9514篇 |
2010年 | 8202篇 |
2009年 | 7761篇 |
2008年 | 7436篇 |
2007年 | 6838篇 |
2006年 | 6436篇 |
2005年 | 5345篇 |
2004年 | 3777篇 |
2003年 | 3073篇 |
2002年 | 3011篇 |
2001年 | 2537篇 |
2000年 | 2193篇 |
1999年 | 2066篇 |
1998年 | 1477篇 |
1997年 | 1173篇 |
1996年 | 1168篇 |
1995年 | 918篇 |
1994年 | 703篇 |
1993年 | 554篇 |
1992年 | 449篇 |
1991年 | 293篇 |
1990年 | 238篇 |
1989年 | 167篇 |
1988年 | 175篇 |
1987年 | 91篇 |
1986年 | 89篇 |
1985年 | 55篇 |
1984年 | 38篇 |
1983年 | 28篇 |
1982年 | 27篇 |
1981年 | 17篇 |
1980年 | 16篇 |
1979年 | 17篇 |
1977年 | 10篇 |
1976年 | 12篇 |
1959年 | 9篇 |
1951年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Bin Feng Xin Jiang Guisheng Zou Wengan Wang Tianming Sun Heng Yang Guanlei Zhao Mingye Dong Yu Xiao Hongwei Zhu Lei Liu 《Advanced functional materials》2021,31(29):2102359
The realization of liquid metal-based wearable systems will be a milestone toward high-performance, integrated electronic skin. However, despite the revolutionary progress achieved in many other components of electronic skin, liquid metal-based flexible sensors still suffer from poor sensitivity due to the insufficient resistance change of liquid metal to deformation. Herein, a nacre-inspired architecture composed of a biphasic pattern (liquid metal with Cr/Cu underlayer) as “bricks” and strain-sensitive Ag film as “mortar” is developed, which breaks the long-standing sensitivity bottleneck of liquid metal-based electronic skin. With 2 orders of magnitude of sensitivity amplification while maintaining wide (>85%) working range, for the first time, liquid metal-based strain sensors rival the state-of-art counterparts. This liquid metal composite features spatially regulated cracking behavior. On the one hand, hard Cr cells locally modulate the strain distribution, which avoids premature cut-through cracks and prolongs the defect propagation in the adjacent Ag film. On the other hand, the separated liquid metal cells prevent unfavorable continuous liquid-metal paths and create crack-free regions during strain. Demonstrated in diverse scenarios, the proposed design concept may spark more applications of ultrasensitive liquid metal-based electronic skins, and reveals a pathway for sensor development via crack engineering. 相似文献
32.
Jun Dong Cho Luis Cavazos Quero Jorge Iranzo Bartolom Do Won Lee Uran Oh Inae Lee 《Color research and application》2021,46(1):103-116
A recent development in tactile technology enables an improvement in the appreciation of the visual arts for people with visual impairment (PVI). The tactile sense, in conjunction with, or a possibly as an alternative to, the auditory sense, would allow PVIs to approach artwork in a more self‐driven and engaging way that would be difficult to achieve with just an auditory stimulus. Tactile colour pictograms (TCPs), which are raised geometric patterns, are ideographic characters that are designed to enable PVIs to identify colours and interpret information by touch. In this article, three TCPs are introduced to code colours in the Munsell colour system. Each colour pattern consists of a basic cell size of 10 mm × 10 mm to represent the patterns consistently in terms of regular shape. Each TCP consists of basic geometric patterns that are combined to create primary, secondary, and tertiary colour pictograms of shapes indicating colour hue, intensity and lightness. Each TCP represents 29 colours including six hues; they were then further expanded to represent 53 colours. Two of them did not increase the cell size, the other increased the cell size 1.5 times for some colours, such as yellow‐orange, yellow, blue, and blue‐purple. Our proposed TCPs use a slightly larger cell size compared to most tactile patterns currently used to indicate colour, but code for more colours. With user experience and identification tests, conducted with 23 visually impaired adults, the effectiveness of the TCPs suggests that they were helpful for the participants. 相似文献
33.
Nan Wu Xiaodong Li Mu Zhang Yi Ren Qi Zhu Haijun Peng Hongqiang Ru Xudong Sun 《Journal of the European Ceramic Society》2021,41(4):2898-2907
Refining ceramic microstructures to the nanometric range to minimize light scattering provides an interesting methodology for developing novel optical ceramic materials. In this work, we reported the fabrication and properties of a new nanocomposite optical ceramic of Gd2O3-MgO. The citric acid sol-gel combustion method was adopted to fabricate Gd2O3-MgO nanocomposites with fine-grain sizes, dense microstructures and homogeneous phase domains. Nanopowders with low agglomeration and improved sinterability can be obtained by elaborating Φ values. Further refining of the microstructure of the nanocomposites was achieved by elaborating the hot-pressing conditions. The sample sintered at 65 MPa and 1300 °C showed a quite high hardness value of 14.3 ± 0.2 GPa, a high transmittance of 80.3 %–84.7 % over the 3?6 μm wavelength range, due mainly to its extremely fine-grain size of Gd2O3 and MgO (93 and 78 nm, respectively) and high density. 相似文献
34.
Fluorescence‐Activated Cell Sorters: Standing Surface Acoustic Wave (SSAW)‐Based Fluorescence‐Activated Cell Sorter (Small 40/2018)
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
35.
针对传统铁矿石磁化焙烧技术与装备存在焙烧产品质量差、产能低、能耗高和环境污染严重等问题,创造性提出了一种“预热-蓄热还原-再氧化”悬浮磁化焙烧新工艺。该工艺具有原料适应性广、焙烧产品质量均匀、回收率高、生产能耗低、无污染等特点,适合处理赤铁矿、褐铁矿、菱铁矿及其混合型难选铁矿石。通过多年的潜心基础研究与技术攻关,形成了非均质矿石颗粒悬浮态流动控制、蓄热式高效低温还原、铁物相精准调控与余热同步回收等一系列关键技术,建成了500kg/h复杂难选铁矿石悬浮磁化焙烧-高效分选半工业试验平台。 相似文献
36.
37.
Chenxu Liu Shuguang Zhang Ruonan Ji Peng Wang Jin Zhang Yu Tian Yonggang Meng Yedong He 《Ceramics International》2019,45(4):4747-4755
Semiconductor particles doped Al2O3 coatings were prepared by cathode plasma electrolytic deposition in Al(NO3)3 electrolyte dispersed with SiC micro- and nano-particles (average particle sizes of 0.5–1.7?µm and 40?nm respectively). The effects of the concentrations and particle sizes of the SiC on the microstructures and tribological performances of the composite coatings were studied. In comparison with the case of dispersing with SiC microparticles, the dispersion of SiC nanoparticles in the coatings was more uniform. When the concentration of SiC nanoparticles was 5?g/L, the surface roughness of the composite coating was reduced by 63%, compared with that of the unmodified coating. Friction results demonstrated that the addition of 5?g/L SiC nanoparticles reduced the friction coefficient from 0.60 to 0.38 and decreased the wear volume under dry friction. The current density and bath voltage were measured to analyze the effects of SiC particles on the deposition process. The results showed that the SiC particles could alter the electrical behavior of the coatings during the deposition process, weaken the bombardment of the plasma, and improve the structures of the coatings. 相似文献
39.
40.