全文获取类型
收费全文 | 20727篇 |
免费 | 4570篇 |
国内免费 | 2450篇 |
专业分类
化学 | 12687篇 |
晶体学 | 575篇 |
力学 | 1314篇 |
综合类 | 207篇 |
数学 | 261篇 |
物理学 | 12703篇 |
出版年
2024年 | 27篇 |
2023年 | 151篇 |
2022年 | 427篇 |
2021年 | 584篇 |
2020年 | 650篇 |
2019年 | 544篇 |
2018年 | 585篇 |
2017年 | 699篇 |
2016年 | 923篇 |
2015年 | 868篇 |
2014年 | 1071篇 |
2013年 | 1948篇 |
2012年 | 1348篇 |
2011年 | 1371篇 |
2010年 | 1171篇 |
2009年 | 1314篇 |
2008年 | 1269篇 |
2007年 | 1480篇 |
2006年 | 1430篇 |
2005年 | 1164篇 |
2004年 | 1064篇 |
2003年 | 988篇 |
2002年 | 860篇 |
2001年 | 766篇 |
2000年 | 719篇 |
1999年 | 642篇 |
1998年 | 538篇 |
1997年 | 478篇 |
1996年 | 398篇 |
1995年 | 355篇 |
1994年 | 311篇 |
1993年 | 302篇 |
1992年 | 228篇 |
1991年 | 148篇 |
1990年 | 148篇 |
1989年 | 110篇 |
1988年 | 133篇 |
1987年 | 89篇 |
1986年 | 80篇 |
1985年 | 53篇 |
1984年 | 59篇 |
1983年 | 18篇 |
1982年 | 48篇 |
1981年 | 48篇 |
1980年 | 29篇 |
1979年 | 28篇 |
1978年 | 26篇 |
1977年 | 13篇 |
1974年 | 9篇 |
1973年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
提出了折射率温敏式光纤温度传感器的理论模型,包括子午光线和偏射光线的影响,讨论了多模光纤的弯曲损耗,理论的分析和结果与实验相当一致。 相似文献
72.
73.
W. Kockelmann M. Hofmann O. Moze S.J. Kennedy K.H.J. Buschow 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(1):25-32
The element distributions and the magnetic ordering behaviour of compounds RNi10Si2 (R
=
Tb, Dy, Ho, Er, Tm) have been studied by neutron powder diffraction down to temperatures of 1.6 K. The compounds crystallize
in an ordered variant of the ThMn12 structure type in the tetragonal space group P4/nmm. An ordered 1:1 distribution of Ni and Si on sites 4d and 4e, respectively,
corresponds to a modulation vector [0, 0, 1] with respect to the space group I4/mmm of the ThMn12 structure. TbNi10Si2 orders antiferromagnetically below T
N
= 4.5 K with a magnetic propagation vector of [0, 0, 1/2]. The magnetic Tb moments, 8.97(2) /Tb atom at 1.6 K, are aligned along the c-axis. The Ni sites in TbNi10Si2 do not carry any ordered magnetic moments. The compounds with R
=
Dy, Ho, Er, and Tm are paramagnetic down to 1.6 K and 3.0 K, respectively.
Received 10 July 2002 / Received in final form 12 September 2002 Published online 29 October 2002 相似文献
74.
G. Carelli N. Ioli A. Messina A. Moretti S. Schepis F. Strumia 《International Journal of Infrared and Millimeter Waves》1998,19(9):1191-1199
We measured the dependence of the reflectivity of InSb crystals upon temperature in the submillimeter region using monochromatic radiation from an optically pumped far infrared (FIR) laser. The measures allowed us to determine the value of the electron effective mass at low temperatures with radiations of different frequencies. Our measurements extend the results obtained recently on pure crystals with magneto-optical methods to the low temperatures region where only old measures were available. 相似文献
75.
76.
77.
M. U. Belyi N. E. Bartnitskaya I. F. Mel'nik B. A. Okhrimenko S. M. Yablochkov 《Journal of Applied Spectroscopy》1995,62(3):564-567
T. Shevchenko Kiev University, 252022 Kiev, Pr. Akad. Glushakova, 6, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 62, No. 3, pp. 192–196, May–June, 1995. 相似文献
78.
Ryohei Tsuda Sayaka Kaino Hisashi Kokubo Shin-Ichiro Imabayashi Masayoshi Watanabe 《Colloids and surfaces. B, Biointerfaces》2007,56(1-2):255-Optics
Redox properties of phenothiazine-labeled poly(ethyl glycidy ether)-block-poly(ethylene oxide) (PT-EGEn-b-EOm) are reversibly changed by core-shell micelle formation. In the temperature range higher than the critical micellization temperature (cmt), the anodic potential of PT group positively shifts and concomitantly its anodic current decrease, or levels off compared to those of the reference polymer PT-EOm without the thermo-responsive EGEn segment. The former alteration is caused by incorporation of hydrophobic PT groups into a core of the micelle and the latter by the decrease in the diffusion coefficient of PT groups due to formation of the core-shell micelles. The cmt value and the temperature-dependent alteration in the redox properties strongly depend on the polymer structure, especially the length of thermo-responsive EGEn segment. The electrochemically determined hydrodynamic radii of the polymer aggregates seem to be overestimated, compared to the values reported for the aggregates of other thermo-responsive polymers with similar molecular weights, implying the presence of electrochemically inactive PT groups in the copolymers having longer thermo-responsive segments. 相似文献
79.
80.
I. A. Anoshko V. S. Ermachenko L. E. Sandrigailo 《Journal of Applied Spectroscopy》2007,74(1):102-106
We present the results of a spectroscopic study of a nonequilibrium plasma in a Hall accelerator, in particular for such an
important parameter as the electron temperature. For the studied conditions, we used the semicoronal equilibrium model, which
relates the intensity ratios for two successive ionization steps for the same element.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 93–96, January–February, 2007. 相似文献