全文获取类型
收费全文 | 3890篇 |
免费 | 1362篇 |
国内免费 | 1693篇 |
专业分类
化学 | 3215篇 |
晶体学 | 191篇 |
力学 | 58篇 |
综合类 | 75篇 |
数学 | 96篇 |
物理学 | 3310篇 |
出版年
2024年 | 35篇 |
2023年 | 127篇 |
2022年 | 177篇 |
2021年 | 180篇 |
2020年 | 102篇 |
2019年 | 117篇 |
2018年 | 61篇 |
2017年 | 113篇 |
2016年 | 163篇 |
2015年 | 131篇 |
2014年 | 302篇 |
2013年 | 226篇 |
2012年 | 290篇 |
2011年 | 269篇 |
2010年 | 238篇 |
2009年 | 239篇 |
2008年 | 370篇 |
2007年 | 289篇 |
2006年 | 285篇 |
2005年 | 343篇 |
2004年 | 282篇 |
2003年 | 317篇 |
2002年 | 258篇 |
2001年 | 244篇 |
2000年 | 199篇 |
1999年 | 213篇 |
1998年 | 162篇 |
1997年 | 217篇 |
1996年 | 172篇 |
1995年 | 161篇 |
1994年 | 107篇 |
1993年 | 96篇 |
1992年 | 112篇 |
1991年 | 93篇 |
1990年 | 99篇 |
1989年 | 112篇 |
1988年 | 19篇 |
1987年 | 12篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
排序方式: 共有6945条查询结果,搜索用时 15 毫秒
61.
We model the recent experimental results and demonstrate that the internal shrinkage of nanocavities in silicon is intrinsically associated with preferential amorphization as induced by self-ion irradiation. The results reveal novel thermodynamic nonequilibrium properties of such an open-volume nanostructure in condensed matter and also of covalently bound amorphous materials both at nanosize scale and during ultrafast interaction with energetic beam. 相似文献
62.
We study the electronic energy levels and probability distribution of vertically stacked self-assembled InAs quantum discs system in the presence of a vertically applied electric field. This field is found to increase the splitting between the symmetric and antisymmetric levels for the same angular momentum. The field along the direction from one disc to another affects the electronic energy levels similarly as that in the opposite direction because the two discs are identical. It is obvious from our calculation that the probability of finding an electron in one disc becomes larger when the field points from this disc to the other one. 相似文献
63.
由于腔模与激子对压力的依赖关系不同,所以可以选择不同的压力使激子和光场处于不同的耦合状态,从而实现对耦合的调谐。利用这种办法,我们观测到了代表激子与光场强耦合作用的Rabi分裂。由于在我们现有样品结构中压力对激子本征行为的影响很小,与以前报道的温度、电场等调谐方式相比,这种调谐方法不仅可以有效地调谐半导体微腔内激子与腔模的耦合程度,而且能够保持激子的本征性质在整个调谐过程中基本不变。这有助于研究在强耦合过程中激子极化激元的本征性质。将实验结果与压力下激子与腔模耦合理论进行拟合,得出了正确的Rabi分裂值。 相似文献
64.
We study the oscillator strengths of the optical transitions of the vertically stacked self-assembled InAs quantum discs.The oscillator strengths change evidently when the two quantum discs are far apart from each other.A vertically applied electric field affects the oscillator strengths severely.while the oscillator strengths change slowly as the radius of one disc increases.We also studied the excitonic energy of the system.including the Coulomb interaction.The excitonic energy increases with the increasing radius of one disc.but decreases as a vertically applied electric field increases. 相似文献
65.
66.
We study the two samples of AlInGaN,i.e.,1-μm Gan grown at 1030℃ on the buffer and followed by a 0.6μm-thick epilayer of AlInGaN under the low pressure of 76 Torr and the AlInGaN layer deposited diectly on the buffer layer without the high-temperature GaN layer,by temperature-dependent photoluminescence(PL) spectroscopy and picosecond time-resolved photoluminescence(TRPL) spectroscopy.The TRPL signals of both the samples were fitted well as a stretched exponential decay at all temperatures,indicating significant disorder in the material.We attribute the disorder to nanoscale quantum dots or discs of high indium concentration.Temperature dependence of dispersive exponent β shows that the stretched exponential decay of the two samples comes from dfferent mechanisms.The different depths of the localization potential account for the difference,which is illustrated by the results of temperature dependence of radiative recombination lifetime and PL peak energy. 相似文献
67.
Modified Photoluminescence by Silicon-Based One-Dimensional Photonic Crystal Microcavities
下载免费PDF全文
![点击此处可从《中国物理快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
photoluminescence (PL) lrom one-dimensional photonic band structures is investigated. The doped photonic crystal with microcavitles are fabricated by using alternating hydrogenated amorphous silicon nitride (a-SiNx:H/a-SiNy:H) layers in a plasma enhanced chemical vapour deposition (PECVD) chamber. It is observed that microcavities strongly modify the PL spectra from active hydrogenated amorphous silicon nitride (a-SiNx:H) thin film. By comparison, the wide emission band width 208nm is strongly narrowed to 11 nm, and the resonant enhancement of the peak PL intensity is about two orders of magnitude with respect to the emission of the λ/2-thick layer of a-SiNx:H. A linewidth of Δλ=11 nm and a quality factor of Q=69 are achieved in our one-dimensional a-SiNz photonic crystal microcavities. Measurements of transmittance spectra of the as-grown samples show that the transmittance resonant peak of a cavity mode at 710nm is introduced into the band gap of one-dimensional photonic crystal distributed Bragg reflector (DBR), which further verifies the microcavity effects. 相似文献
68.
介绍了非晶半导体薄膜的结构特点和在光电器件上的独特性能,给出了薄膜器件的发展水平和制膜技术、制膜设备的研究现状。 相似文献
69.
70.
近年来半导体激光器的发展引人注目,已由红外波段推向可见光区,可靠性和输出功率提高而价格下降,在光谱研究方面的应用也日益广泛。文章介绍了半导体激光器的现状,频率稳定、压缩线宽和调谐波长的方法,以及半导体激光器在吸收光谱、非线性光谱、原子的冷却和光泵浦原子钟等方面的应用。 相似文献