全文获取类型
收费全文 | 446篇 |
免费 | 17篇 |
国内免费 | 22篇 |
专业分类
化学 | 191篇 |
晶体学 | 12篇 |
力学 | 11篇 |
数学 | 29篇 |
物理学 | 242篇 |
出版年
2022年 | 8篇 |
2021年 | 10篇 |
2020年 | 13篇 |
2019年 | 14篇 |
2018年 | 15篇 |
2017年 | 26篇 |
2016年 | 19篇 |
2015年 | 5篇 |
2014年 | 13篇 |
2013年 | 27篇 |
2012年 | 18篇 |
2011年 | 29篇 |
2010年 | 22篇 |
2009年 | 19篇 |
2008年 | 20篇 |
2007年 | 20篇 |
2006年 | 26篇 |
2005年 | 15篇 |
2004年 | 17篇 |
2003年 | 18篇 |
2002年 | 19篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 8篇 |
1998年 | 2篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1993年 | 2篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 5篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1967年 | 1篇 |
1966年 | 3篇 |
1965年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有485条查询结果,搜索用时 46 毫秒
91.
Exploration for Degradation of Λ Polarization Produced in Relativistic Nucleus Nucleus Collisions
下载免费PDF全文
![点击此处可从《中国物理C(英文版)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
YE YunXiu CHEN Zhi RUAN TuNan SHEN Ji LV HaiJiang DONG WeiJiang SA BenHao TAI An 《中国物理C(英文版)》2000,24(2):125-130
The degradation of Λ transverse polarization produced in S+Pb central collisions at energy 200 GeV per nucleon has been studied in detail. The S+Pb central collision events have been generated using Monte-Carlo generator——LUCIAE at 200 GeV per nucleon. The various factors degrading Λ transverse polarization have been analysed quantitatively. The ratios of Λ′s produced from rescattering, secondary production and decays of Σ, Ξ hyperons to the total measurable Λ′s in experiment have been investigeted and the degradation effect of these Λ on the total polarization has been determined. The simulation and calculation show that above three factors decrease the Λ transverse polarization strongly, however, can not eliminate the polarization completely when the Λ′s are assumed to be produced from hadronic gas in the final state. To explan the experimental data of vanished Λ polarization, it probably needs to consider new mechanisms of Λ production, including a weak effect of QGP formation. 相似文献
92.
93.
V. E. Korsukov S. A. Knyazev P. N. Butenko V. L. Gilyarov M. M. Korsukova I. A. Nyapshaev B. A. Obidov 《Physics of the Solid State》2017,59(2):316-320
A change in the surface morphology of recrystallized tungsten foil under the effect of uniaxial tension in ultrahigh vacuum is studied by low-energy electron diffraction and atomic force microscopy. It is found by using low-energy electron diffraction that on the foil surface consisting of separate blocks with dominant face (112), there is a turn in orientation of the structural blocks. The analysis of the topograms of different areas of the side surface of a broken sample, obtained by atomic force microscopy, enabled the association of changes in the atomic structure of the surface layers of foil with a change in its relief by mechanical action. 相似文献
94.
Ellipsometric investigations of the optical properties of Ru2Ge3 and Ru2Sn3 intermetallic compounds are carried out in the wavelength range from 0.22 to 15 μm. The nature of interband light absorption is analyzed based on a comparative analysis of the experimental and theoretical frequency dependences of an optical conductivity. The obtained results confirm the existence of energy gaps at the Fermi level in the electronic spectra of these materials predicted earlier by the band-structure calculations. 相似文献
95.
L. A. Dobrun A. P. Kovshik E. I. Ryumtsev Yu. G. Galyametdinov A. A. Knyazev 《Optics and Spectroscopy》2017,122(5):813-815
The values of optical anisotropy of two series of thermotropic nematic liquid crystalline complexes based on the ions Eu+3, Gd+3, Tb+3, and Dy+3 have been determined. Even–odd alternation of optical anisotropy with an increasing number of protons in ions of lanthanides has been observed. It is established that, in the considered series of lanthanidomesogens, optical anisotropy is more sensitive to changes in the ligand structure of complexes than to the variation of the complexing agent. 相似文献
96.
基于尖晶石晶体结构信息,本文采用热力学三亚晶格模型,将材料热力学计算和第一性原理计算相结合,研究了Zn_xMn_(1-x) Fe_2O_4和Ni_xMn_(1-x)Fe_2O_4立方相中的Zn~(2+)、Ni~(2+)、Mn~(2+)以及Fe~(3+)在8a和16d亚晶格上的占位有序化行为。结果表明:在锰铁氧体中,室温下Mn~(2+)完全占据在8a亚晶格上,Fe~(3+)完全占据在16d亚晶格上,属于正尖晶石结构;随着热处理温度升高,在1 273 K达到热处理平衡时的占位构型为(Fe~(3+)0.09Mn~(2+)0.91)[Fe~(3+)1.91Mn~(2+)0.09]O_4,在热处理温度升至1 473 K时,达到热处理平衡时的占位构型为(Fe~(3+)0.11Mn~(2+)0.89)[Fe~(3+)1.89Mn~(2+)0.11]O_4,均与实验结果符合较好。在锌铁氧体中,室温下Zn~(2+)完全占据在8a亚晶格上,Fe~(3+)完全占据在16d亚晶格上,属于正尖晶石结构;在热处理温度较高时,Zn~(2+)和Fe~(3+)发生部分置换,符合实验结果。在镍铁氧体中,半数的Fe~(3+)在室温下占据在8a亚晶格上,Ni~(2+)与剩下另一半的Fe~(3+)共同占据在16d亚晶格上,仅在热处理温度较高的时候发生微弱变化,亦与已有的实验结果吻合。在此基础上,本文进一步通过热力学模型研究了立方相尖晶石结构的Zn_xMn_(1-x)Fe_2O_4、Ni_xMn_(1-x)Fe_2O_4复合体系中阳离子占位行为与热处理温度对占位的影响规律。 相似文献
97.
Yu. V. Knyazev A. V. Lukoyanov Yu. I. Kuz’min A. Haldar K. G. Suresh 《Optics and Spectroscopy》2014,117(3):414-418
Optical properties of two intermetallic compounds TbNi4Fe and TbNi4Co have been studied employing ellipsometry in a spectral range 0.22–15 μm to reveal their characteristic features in comparison with the parent compound TbNi5. The electronic structure of TbNi4Fe and TbNi4Co was calculated within the LSDA + U method (local spin density approximation with Hubbard U-correction). Based on the calculated electronic structure results, the theoretical optical conductivity was calculated and used to interpret experimental conductivity in the range of interband optical absorption. 相似文献
98.
Within the class of exact solutions of the thermal-convection equations in the Oberbeck-Boussinesq approximation, which assumes a linear dependence of the temperature and the vertical velocity component on the height, a non-self-similar behavior of localized disturbances of a special type in a nonuniformly heated liquid layer is studied. It is shown that in an unstably stratified medium these disturbances can evolve to isothermal vortex structures of Burgers type. In the conditions of stable stratification or uniform heating of the layer, the disturbances considered tend to the state of rest in an oscillating or monotonic manner. New solutions describing self-similar convective vortices are found. 相似文献
99.
I.A. Nekrasov E.E. Kokorina V.A. Galkin Yu.I. Kuz'min Yu.V. Knyazev A.G. Kuchin 《Physica B: Condensed Matter》2012,407(17):3600-3603
In this paper we present theoretical investigation of optical conductivity for intermetallic TbNi5−xCux series. Within the framework of LSDA+U calculations, electronic structure for x=0, 1, 2 is calculated and additionally optical conductivity is obtained. Disorder effects of Cu for Ni substitution on a level of LSDA+U densities of states (DOS) are taken into account via averaging over all possible Cu ion positions in the unit cell for given doping level x. Gradual smoothing of optical conductivity structure at 2 eV together with simultaneous intensity growth at 4 eV corresponds to increase of Cu and decrease of Ni content. 相似文献
100.
采用傅里叶变换红外光谱(FTIR)及其二阶导数谱对不同生长年限当归药材进行分析研究.结果表明,不同生长年限当归药材的红外图谱较为相似,仅从一维谱图上无法反映出不同生长年限当归药材的红外特征谱明显的异同,但通过二阶导数图谱中1771、1747、1712、1559、1514、1466、766、711cm-1和668cm-1处的峰型差异可发现不同生长年限当归药材之间的一些成分存在较明显的差异.由于生长时间不同,导致它们的化学成分存在差异,所以体现了各自的红外特征谱,其中第三年当归药材与第一年和第二年当归药材间差异较大. 相似文献