全文获取类型
收费全文 | 52篇 |
免费 | 72篇 |
国内免费 | 77篇 |
专业分类
化学 | 73篇 |
晶体学 | 1篇 |
力学 | 7篇 |
数学 | 20篇 |
物理学 | 100篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 15篇 |
2011年 | 14篇 |
2010年 | 12篇 |
2009年 | 24篇 |
2008年 | 15篇 |
2007年 | 18篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 8篇 |
2001年 | 2篇 |
2000年 | 19篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有201条查询结果,搜索用时 15 毫秒
91.
3-氨基-1,2,4-三氮唑自组装膜对黄铜的缓蚀作用 总被引:7,自引:0,他引:7
3-氨基-1,2,4-三氮唑(ATA)是一种环境友好型金属处理剂, 以其在黄铜表面制备了自组装单分子膜(SAMs), 用电化学方法研究ATA SAMs对黄铜的缓蚀作用及其吸附行为. 结果表明, ATA分子易在黄铜表面形成稳定的ATA SAMs, SAMs抑制了黄铜的阳极氧化过程, 改变了电极表面的双电层结构, 固/液界面双电层电容明显降低, 有良好的缓蚀效果. 研究结果还表明, ATA的吸附行为符合Langmuir吸附等温式, 吸附机理是典型的化学吸附. 相似文献
92.
Shiang-Kuo Chang-Jian Jeng-Rong Ho J.-W. John Cheng 《Applied Physics A: Materials Science & Processing》2011,105(3):691-696
A novel laser-separation method for fabrication and patterning of free-standing carbon nanotube buckypapers is reported in
this study. By introducing a patterned mask, buckypapers having surface patterns could be straightforwardly fabricated; and,
through a shaped support, buckypapers possessing three-dimensional curved surfaces were directly demonstrated. Property measurements
indicated that the laser irradiation had unapparent effects on the buckypapers’ electrical conductivity and field-emission
characteristics. In addition, based on this approach, thin buckypapers, with thickness around 15 μm, could be constantly fabricated
that demonstrates the superiority over the available mass-produced methods for which buckypapers with thickness smaller than
50 μm still present challenges. 相似文献
93.
Chang-Jian Weng Chih-Wei Peng Ya-Han Chang Kuan-Cheng Chiu Jui-Ming Yeh 《Journal of Non》2011,357(1):227-231
Electroactive silica mesopores have been synthesized by encapsulating different loadings of polyaniline chains into a silica network through sol-gel reactions of TEOS in the presence of polyaniline latex with D-glucose. It should be noted that the electroactive silica mesopores at higher polyaniline loading was found to reveal higher surface areas, larger pore volume, and slightly larger pore diameters as compared to that of neat non-electroactive silica mesopores. 相似文献
94.
Chang-Jian Zhao 《Applied Mathematics Letters》2012,25(2):190-194
In the paper, we establish a reversed Dresher’s integral inequality, based on the Minkowski inequality and an inequality due to Radon. Further, we prove Dresher-type inequalities for width-integrals of convex bodies and mixed projection bodies, respectively. 相似文献
95.
96.
This study performs a systematic analysis of the dynamic behavior of a gear-bearing system with the turbulent flow effect, nonlinear suspension, nonlinear oil-film force and nonlinear gear mesh force. The dynamic orbits of the system are observed using bifurcation diagrams plotted using the dimensionless damping coefficient, unbalance coefficient and the dimensionless rotational speed ratio as control parameters. The onset of chaotic motion is identified from the phase diagrams, power spectra, Poincaré maps, Lyapunov exponents and fractal dimension of the gear system. The numerical results reveal that the system exhibits a diverse range of periodic, sub-harmonic and chaotic behaviors. The results presented in this study provide a detailed understanding of the operating conditions under which undesirable dynamic motion takes place in gear-bearing system and therefore offer a useful source of reference for engineers in designing and controlling such systems. 相似文献
97.
98.
In this paper, we first introduce a new concept ofdual quermassintegral sum function of two star bodies and establish Minkowski’s type inequality for dual quermassintegral sum of mixed intersection bodies,
which is a general form of the Minkowski inequality for mixed intersection bodies. Then, we give the Aleksandrov-Fenchel inequality
and the Brunn-Minkowski inequality for mixed intersection bodies and some related results. Our results present, for intersection
bodies, all dual inequalities for Lutwak’s mixed prosection bodies inequalities. 相似文献
99.
Growth of Strain Free GaN Layers on (0001) Oriented Sapphire by Using Quasi-Porous GaN Template 总被引:1,自引:0,他引:1 下载免费PDF全文
We report the reduced-strain gallium-nitride (GaN) epitaxial growth on (0001) oriented sapphire by using quasiporous GaN template. A GaN film in thickness of about 1 μm was initially grown on a (0001) sapphire substrate by molecular beam epitaxy. Then it was dealt by putting into 45% NaOH solution at 100℃ for lOmin. By this process a quasi-porous GaN film was formed. An epitaxial GaN layer was grown on the porous GaN layer at 1050℃ in the hydride vapour phase epitaxy reactor. The epitaxial layer grown on the porous GaN is found to have no cracks on the surface. That is much improved from many cracks on the surface of the GaN epitaxial layer grown on the sapphire as the same as on GaN buffer directly. 相似文献
100.