全文获取类型
收费全文 | 217篇 |
免费 | 34篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 14篇 |
综合类 | 15篇 |
化学工业 | 32篇 |
金属工艺 | 9篇 |
机械仪表 | 23篇 |
建筑科学 | 14篇 |
矿业工程 | 9篇 |
能源动力 | 9篇 |
轻工业 | 12篇 |
水利工程 | 5篇 |
石油天然气 | 13篇 |
无线电 | 32篇 |
一般工业技术 | 28篇 |
冶金工业 | 14篇 |
原子能技术 | 3篇 |
自动化技术 | 28篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 3篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 18篇 |
2012年 | 10篇 |
2011年 | 11篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 14篇 |
2007年 | 13篇 |
2006年 | 10篇 |
2005年 | 6篇 |
2004年 | 10篇 |
2003年 | 12篇 |
2002年 | 11篇 |
2001年 | 9篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1966年 | 1篇 |
1963年 | 2篇 |
排序方式: 共有260条查询结果,搜索用时 515 毫秒
41.
42.
Jae Hoon Yang Hyoung Woo Yang Byoung Ok Jun Jeong Hee Shin Seunguk Kim A‐Rang Jang Seong In Yoon Hyeon Suk Shin Deoksoo Park Kyungho Park Duhee Yoon Jung Inn Sohn SeungNam Cha Dae Joon Kang Jae Eun Jang 《Advanced functional materials》2019,29(18)
Graphene has been gradually studied as a high‐frequency transmission line material owing to high carrier mobility with frequency independence up to a few THz. However, the graphene‐based transmission lines have poor conductivity due to their low carrier concentration. Here, it is observed that the radio frequency (RF) transmission performance could be severely hampered by the defect‐induced scattering, even though the carrier concentration is increased. As a possible solution, the deposition of the amorphous carbon on the graphene is studied in the high‐frequency region up to 110 GHz. The DC resistance is reduced by as much as 60%, and the RF transmission property is also enhanced by 3 dB. Also, the amorphous carbon covered graphene shows stable performance under a harsh environment. These results prove that the carrier concentration control is an effective and a facile method to improve the transmission performance of graphene. It opens up the possibilities of using graphene as interconnects in the ultrahigh‐frequency region. 相似文献
43.
44.
Eun Kwang Lee Moo Yeol Lee Cheol Hee Park Hae Rang Lee Joon Hak Oh 《Advanced materials (Deerfield Beach, Fla.)》2017,29(44)
Recent interest in flexible electronics has led to a paradigm shift in consumer electronics, and the emergent development of stretchable and wearable electronics is opening a new spectrum of ubiquitous applications for electronics. Organic electronic materials, such as π‐conjugated small molecules and polymers, are highly suitable for use in low‐cost wearable electronic devices, and their charge‐carrier mobilities have now exceeded that of amorphous silicon. However, their commercialization is minimal, mainly because of weaknesses in terms of operational stability, long‐term stability under ambient conditions, and chemical stability related to fabrication processes. Recently, however, many attempts have been made to overcome such instabilities of organic electronic materials. Here, an overview is provided of the strategies developed for environmentally robust organic electronics to overcome the detrimental effects of various critical factors such as oxygen, water, chemicals, heat, and light. Additionally, molecular design approaches to π‐conjugated small molecules and polymers that are highly stable under ambient and harsh conditions are explored; such materials will circumvent the need for encapsulation and provide a greater degree of freedom using simple solution‐based device‐fabrication techniques. Applications that are made possible through these strategies are highlighted. 相似文献
45.
Jae‐Bok Lee Yi Rang Lim Ajit K. Katiyar Wooseok Song Jongsun Lim Sukang Bae Tae‐Wook Kim Seoung‐Ki Lee Jong‐Hyun Ahn 《Advanced materials (Deerfield Beach, Fla.)》2019,31(43)
Functional van der Waals heterojunctions of transition metal dichalcogenides are emerging as a potential candidate for the basis of next‐generation logic devices and optoelectronics. However, the complexity of synthesis processes so far has delayed the successful integration of the heterostructure device array within a large scale, which is necessary for practical applications. Here, a direct synthesis method is introduced to fabricate an array of self‐assembled WSe2/MoS2 heterostructures through facile solution‐based directional precipitation. By manipulating the internal convection flow (i.e., Marangoni flow) of the solution, the WSe2 wires are selectively stacked over the MoS2 wires at a specific angle, which enables the formation of parallel‐ and cross‐aligned heterostructures. The realized WSe2/MoS2‐based p–n heterojunction shows not only high rectification (ideality factor: 1.18) but also promising optoelectrical properties with a high responsivity of 5.39 A W?1 and response speed of 16 µs. As a feasible application, a WSe2/MoS2‐based photodiode array (10 × 10) is demonstrated, which proves that the photosensing system can detect the position and intensity of an external light source. The solution‐based growth of hierarchical structures with various alignments could offer a method for the further development of large‐area electronic and optoelectronic applications. 相似文献
46.
Most camera images are saved as 8-bit standard RGB (sRGB) compressed JPEGs. Even when JPEG compression is set to its highest quality, the encoded sRGB image has been significantly processed in terms of color and tone manipulation. This makes sRGB–JPEG images undesirable for many computer vision tasks that assume a direct relationship between pixel values and incoming light. For such applications, the RAW image format is preferred, as RAW represents a minimally processed, sensor-specific RGB image that is linear with respect to scene radiance. The drawback with RAW images, however, is that they require large amounts of storage and are not well-supported by many imaging applications. To address this issue, we present a method to encode the necessary data within an sRGB–JPEG image to reconstruct a high-quality RAW image. Our approach requires no calibration of the camera’s colorimetric properties and can reconstruct the original RAW to within 0.5% error with a small memory overhead for the additional data (e.g., 128 KB). More importantly, our output is a fully self-contained 100% compliant sRGB–JPEG file that can be used as-is, not affecting any existing image workflow—the RAW image data can be extracted when needed, or ignored otherwise. We detail our approach and show its effectiveness against competing strategies. 相似文献
47.
48.
超/特高压交直流并行线路带电作业区域电压高、场强大,为保证并行线路带电作业的安全开展,需要对
带电作业人员安全防护进行研究。分析了带电作业的安全影响因素,依据线路实际尺寸建立了1∶1计算模型,
采用有限元法对同走廊四回并行线路进行了电场仿真,获得了带电作业典型位置点的电场强度,根据仿真结果
对带电作业人员电位转移放电能量进行了计算。同时建立了人体模型,计算分析了等电位作业工况下人体不同
部位的电场强度特点。计算结果表明:同电压等级独立走廊带电作业安全防护措施同样适合于四回并行线路带
电作业。提出了相应的安全防护措施,研究结果可为同走廊多回并行线路带电作业的开展提供依据和技术支撑
。 相似文献
49.
本文分析了闹德海水库泥沙淤积特性以及年际年内库区冲淤的变化规律,通过实测资料列表对比分析表明,水库要想保持一个长期稳定的库容,必须加强洪水预报工作,一定要在峰前把库水放空。 相似文献
50.