全文获取类型
收费全文 | 2458篇 |
免费 | 148篇 |
国内免费 | 16篇 |
专业分类
化学 | 1925篇 |
晶体学 | 23篇 |
力学 | 82篇 |
数学 | 114篇 |
物理学 | 478篇 |
出版年
2024年 | 3篇 |
2023年 | 14篇 |
2022年 | 21篇 |
2021年 | 69篇 |
2020年 | 43篇 |
2019年 | 60篇 |
2018年 | 41篇 |
2017年 | 42篇 |
2016年 | 95篇 |
2015年 | 93篇 |
2014年 | 118篇 |
2013年 | 159篇 |
2012年 | 270篇 |
2011年 | 255篇 |
2010年 | 151篇 |
2009年 | 136篇 |
2008年 | 189篇 |
2007年 | 157篇 |
2006年 | 146篇 |
2005年 | 124篇 |
2004年 | 100篇 |
2003年 | 93篇 |
2002年 | 87篇 |
2001年 | 36篇 |
2000年 | 21篇 |
1999年 | 20篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 10篇 |
1994年 | 4篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有2622条查询结果,搜索用时 16 毫秒
131.
132.
133.
Dependence of electrical performance on structural organization in polymer field effect transistors
下载免费PDF全文
![点击此处可从《Journal of Polymer Science.Polymer Physics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Emily G. Bittle Hyun Wook Ro Chad R. Snyder Sebastian Engmann R. Joseph Kline Xinran Zhang Oana D. Jurchescu Dean M. DeLongchamp David J. Gundlach 《Journal of Polymer Science.Polymer Physics》2017,55(14):1063-1074
Organic semiconductors (OSCs) are strong contenders for use in printed, flexible electronics. Although organic electronic materials have been studied for many years, the physics of charge transport is still under investigation. This is in part due to variability resulting from the large variety of molecules that can be synthesized and inconsistency in electrical characterization due to device and processing conditions. Molecular ordering in OSCs is known to alter the charge transport characteristics and attention to long range and short range ordering provides clues as to the nature of transport pathways. Here, we study ordered regioregular poly(3‐hexylthiophene‐2,5‐diyl) films carefully prepared to obtain a set of three samples with incrementally increasing order on identical transistor architectures. Ordering was characterized using a variety of short and long range techniques to probe the coherence and number of crystallites formed during processing, and the correlation between these different measures of order are quantified. We observe three changes in transistor behavior that show a shift from non‐ideal to more textbook‐like characteristics with increasing order: reduction of the contact resistance, shift to field‐independent mobility, and a shift from a diode‐like (S‐shaped) to linear response at low lateral fields. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1063–1074 相似文献
134.
135.
Effects of B and P content on structural and magnetic properties of cast iron based amorphous alloys
S. N. Kane H. J. Lee S. B. Kim Y. H. Jeong S. W. Hyun C. S. Kim L. K. Varga 《Hyperfine Interactions》2009,191(1-3):109-113
Mössbauer spectroscopy, DSC and magnetic measurements have been used to study the influence of B and P on structural; magnetic properties and thermal stability of cast iron based alloys. Results reveal that addition of B and P affects appreciably: (1) the crystallization temperature and supercooled liquid region ranging between 690–781 and 53–81 K respectively; (2) the spin texture, disorder and (3) the obtained magnetization parameters. Coercive field values range between 10.09 and 16.37 A/m, with lowest value of 10.09 A/m obtained for Ci87.82B12.17. Saturation induction (B s) values vary between 1.32 and 1.85 T. Highest B s value of 1.85 T is obtained for the Ci95.65B4.32 alloy which is at the edge of glass forming ability, with only 4.32 at.% of boron was added to the cast iron composition. Losses (at 50 Hz and 0.32 kA/m) for the studied samples range between 0.43 and 0.82 W/kg. Lowest losses of 0.43 W/kg was obtained for the Ci91.3P4.35B4.35 alloy. Phosphorous and boron additions, helps in the bulk glass forming ability, suggesting perspective applications of these cheap cast iron based soft magnetic alloys as a substitute of the conventional materials. 相似文献
136.
137.
138.
139.
140.