全文获取类型
收费全文 | 37篇 |
免费 | 15篇 |
国内免费 | 14篇 |
学科分类
数理化 | 66篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 1篇 |
2012年 | 4篇 |
2011年 | 3篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2000年 | 8篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1987年 | 1篇 |
排序方式: 共有66条查询结果,搜索用时 15 毫秒
61.
62.
Investigation of Oxygen Vacancy and Interstitial Oxygen Defects in ZnO Films by Photoluminescence and X-Ray Photoelectron Spectroscopy 下载免费PDF全文
ZnO films prepared at different temperatures and annealed at 900^o C in oxygen are studied by photoluminescence (PL) and x-ray photoelectron spectroscopy (XPS). It is observed that in the PL of the as-grown films the green luminescence (GL) and the yellow luminescence (YL) are related, and after annealing the GL is restrained and the YL is enhanced. The 0 ls XPS results also show the coexistence of oxygen vacancy (Vo) and interstitial oxygen (Oi) before annealing and the quenching of the Vo after annealing. By combining the two results it is deduced that the GL and YL are related to the Vo and Oi defects, respectively. 相似文献
63.
Preparation of multi-walled carbon nanotube–Fe composites and their application as light weight and broadband electromagnetic wave absorbers 下载免费PDF全文
Multi-walled carbon nanotube (MWCNT)-Fe composites were prepared via the metal organic chemical vapor deposi- tion by depositing iron pentacarbonyl on the surface of MWCNTs. The structural and morphological analyses demonstrated that Fe nanoparticles were deposited on the surface of the MWCNTs. The electromagnetic properties of the MWCNTs were significantly changed, and the absorbing capacity evidently improved after the Fe deposition on the MWCNT surface. A minimum reflection loss of -29.4 dB was observed at 8.39 GHz, and the less than -10 dB bandwidth was about 10.6 GHz, which covered the whole X band (8.2-12.4 GHz) and the whole Ku band (12.4-18 GHz), indicating that the MWCNT-Fe composites could be used as an effective microwave absorption material. 相似文献
64.
锂离子电池正极材料LiV3-xMnxO8的水热合成与性能 总被引:1,自引:0,他引:1
采用水热法制备了Mn掺杂改性的锂二次电池钒基层状正极材料LiV3-xMnxO8(x=0.00, 0.01, 0.02, 0.04, 0.06, 0.08, 0.10). 用X射线衍射(XRD)和扫描电镜(SEM)对材料的晶体结构和形貌进行表征, 并以50 mA·g-1的电流对材料进行恒流充放电测试. 研究了Mn掺杂对材料晶体结构和电化学性能的影响. 结果表明, Mn掺杂能够明显改善材料的电化学性能. 在掺杂改性的LiV3-xMnxO8材料中, LiV2.94Mn0.06O8的初始容量最高, 达到295 mAh·g-1. 当掺杂量控制在0.01≤x≤0.08范围内时, LiV3-xMnxO8材料均具有较好的循环性能和充放电可逆性, 经20次循环后放电比容量都保持在120 mAh·g-1以上, 40次循环后都保持在100 mAh·g-1以上, 且材料的充放电效率始终维持在93%以上. 相似文献
65.
66.