全文获取类型
收费全文 | 431篇 |
免费 | 10篇 |
国内免费 | 1篇 |
专业分类
化学 | 292篇 |
晶体学 | 8篇 |
力学 | 2篇 |
数学 | 26篇 |
物理学 | 114篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 17篇 |
2012年 | 19篇 |
2011年 | 40篇 |
2010年 | 19篇 |
2009年 | 12篇 |
2008年 | 18篇 |
2007年 | 25篇 |
2006年 | 16篇 |
2005年 | 13篇 |
2004年 | 30篇 |
2003年 | 22篇 |
2002年 | 13篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 10篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有442条查询结果,搜索用时 8 毫秒
1.
2.
Tetsuo Tsuchiya Akio Watanabe Tomohiko Nakajima Toshiya Kumagai 《Applied Physics A: Materials Science & Processing》2010,101(4):681-684
Europium-doped yttrium oxide (Y2O3:Eu) thin films were successfully deposited on quartz and ITO/glass substrates by excimer-laser-assisted metal organic deposition
(ELAMOD) at low temperatures. The effects of laser wavelength and thermal temperature on the films’ crystallinity and photoluminescence
properties were investigated. Films irradiated by an ArF laser at 80 mJ/cm2 and 400–500°C were highly crystallized compared with those prepared by thermal MOD. In contrast, when the film was irradiated
by a KrF laser at 500°C, no crystalline Y2O3:Eu was formed. The Y2O3:Eu film irradiated by the ArF laser at 80 mJ/cm2 and 500°C showed typical PL spectra of Eu3+ ions with cubic symmetry and a 5D0→7F2 transition at ∼612 nm. The PL intensity at 612 nm was much higher for the film prepared with ELAMOD than for that prepared
by the thermal-assisted process, and the photoemission intensity of the film prepared with ELAMOD strongly depended on the
substrate material. 相似文献
3.
Toshihiko Hoshi Ken-ichi Kumagai Keita Inoue Shigendo Enomoto Yoko Nobe Michio Kobayashi 《Journal of luminescence》2008,128(8):1353-1358
Tris(8-quinolinolato)aluminum(III) (Alq3) shows electronic absorption bands at 378, 360 (in a 1:1 mixed solvent of methanol and ethanol (ME) at 77 K), 334, 316, 300, 263, 255.8, and 233 nm in ethanol at room temperature. According to the polarized fluorescence excitation spectrum together with MO calculations, for instance, the 360 nm band is assigned to an LL CT transition (an intramolecular charge transfer transition between two ligands), and the 378 nm band to an LM/ML CT one (an intramolecular charge transfer transition between ligand and metal). Alq3 shows a broad fluorescence band peaking at around 478 nm in the ME matrix at 77 K. The emission spectrum measured with a phosphoroscope has two emission bands at 567 and 478 nm. The 567 nm band accompanies vibronic bands at 578 and 605 nm, being safely assigned to a phosphorescence of Alq3. The lifetimes of the 478 and 567 nm bands are both 5.4 ms. The lifetime of the 478 nm band together with the band position and its band shape indicate that this band can be assigned to a delayed fluorescence. 相似文献
4.
Masami Kumagai Akihito Taguchi Toshihide Takagahara Takahisa Ohno Kousuke Yakubo 《Solid State Communications》2008,145(3):154-158
The exciton properties of thin nanotube structures are investigated theoretically. Anisotropic size dependencies have been found in the exciton binding energy, the kinetic energy for the relative motions of an electron and a hole, and the wavefunction. These anisotropies arise from the different boundary conditions in the tube-length and circumferential directions, namely, the topological features of nanotubes. We also found that it is possible to change the topology of exciton wavefunctions by varying the tube-length and the tube-radius. These findings suggest that the optical properties of nanotubes such as oscillator strength or nonlinear susceptibilities can be controlled by tuning the structural parameters, thus yielding a novel guiding principle for designing optical functional materials. 相似文献
5.
Annealing behaviors of photo-induced ESR and optically-induced absorption edge shift have been studied in melt-quenched Ge-S glasses with various compositions. Annealing characteristic of photo-induced ESR has been found to be quite parallel to that of optically-induced edge shift. Composition dependence of them is correlated with that of the glass transition temperature. 相似文献
6.
Ca-doped LaMnO3 (LCMO) thin films have been successfully prepared on SrTiO3 (STO) and [(LaAlO3)0.3-(SrAlTaO6)0.7] (LSAT) substrates using the excimer laser assisted metal-organic deposition (ELAMOD) process. The crystallization and the epitaxial growth of the amorphous metal-organic LCMO thin films have been achieved using a KrF excimer laser irradiation while the substrates were kept at constant temperature of 500 °C. Epitaxial films were obtained using laser fluence in the interval of 50-120 mJ/cm2. The microstructure of the LCMO films was studied using cross-section transmission electron microscopy. High quality of LCMO films having smooth surfaces and sharp interfaces were obtained on both the STO and the LSAT substrates. The effect of the laser fluence on the temperature coefficient of resistance (TCR) was investigated. The largest values of TCR of the LCMO grown on the LSAT and the STO substrates of 8.3% K−1 and 7.46% K−1 were obtained at different laser fluence of 80 mJ/cm2 and 70 mJ/cm2, respectively. 相似文献
7.
We developed a deep-UV single-mode coherent light source through two-stage highly efficient frequency conversions by use of external cavities. In the first stage, second-harmonic power of 500 mW was obtained by frequency doubling of a 746-nm Ti:sapphire laser with a conversion efficiency of 40%. In the second stage, 50-mW power at ~252nm was obtained by doubly resonant sum-frequency mixing of 373-nm light from the first-stage conversion and 780-nm light from a diode laser. The output performance of this deep-UV light source is sufficient for laser cooling of neutral silicon atoms. 相似文献
8.
Pat J. Fitzsimmons Ben M. Hambly Takashi Kumagai 《Communications in Mathematical Physics》1994,165(3):595-620
A class of affine nested fractals is introduced which have different scale factors for different similitudes but still have the symmetry assumptions of nested fractals. For these fractals estimates on the transition density for the Brownian motion are obtained using the associated Dirichlet form. An upper bound for the diagonal can be found using a Nash-type inequality, then probabilistic techniques are used to obtain the off-diagonal bound. The approach differs from previous treatments as it uses only the Dirichlet form and no estimates on the resolvent. The bounds obtained are expressed in terms of an intrinsic metric on the fractal. 相似文献
9.
Kosuke KakuyanagiKen-ichi Kumagai Yuji Matsuda 《Journal of Physics and Chemistry of Solids》2002,63(12):2305-2308
We report a site-selective 17O spin-lattice relaxation rate T1−1 in the vortex state of YBa2Cu4O8. We found that T1−1 at the planar sites exhibits an unusual nonmonotonic NMR frequency dependence. Based on T1−1 in the vortex core region, we establish strong evidence that the local density of states within the vortex core is strongly reduced. 相似文献
10.