全文获取类型
收费全文 | 1410271篇 |
免费 | 29960篇 |
国内免费 | 7815篇 |
专业分类
化学 | 716864篇 |
晶体学 | 20559篇 |
力学 | 76124篇 |
综合类 | 110篇 |
数学 | 247252篇 |
物理学 | 387137篇 |
出版年
2021年 | 13637篇 |
2020年 | 16074篇 |
2019年 | 16231篇 |
2018年 | 14433篇 |
2016年 | 29009篇 |
2015年 | 21207篇 |
2014年 | 30790篇 |
2013年 | 75044篇 |
2012年 | 42041篇 |
2011年 | 41856篇 |
2010年 | 39295篇 |
2009年 | 41017篇 |
2008年 | 39873篇 |
2007年 | 36228篇 |
2006年 | 40503篇 |
2005年 | 33598篇 |
2004年 | 33944篇 |
2003年 | 31304篇 |
2002年 | 31967篇 |
2001年 | 32151篇 |
2000年 | 27042篇 |
1999年 | 23605篇 |
1998年 | 21487篇 |
1997年 | 21365篇 |
1996年 | 21391篇 |
1995年 | 19371篇 |
1994年 | 18867篇 |
1993年 | 18459篇 |
1992年 | 18876篇 |
1991年 | 19018篇 |
1990年 | 18233篇 |
1989年 | 18257篇 |
1988年 | 17824篇 |
1987年 | 17751篇 |
1986年 | 16737篇 |
1985年 | 23074篇 |
1984年 | 24140篇 |
1983年 | 20206篇 |
1982年 | 21810篇 |
1981年 | 21037篇 |
1980年 | 20383篇 |
1979年 | 20735篇 |
1978年 | 21907篇 |
1977年 | 21540篇 |
1976年 | 21299篇 |
1975年 | 19997篇 |
1974年 | 19704篇 |
1973年 | 20081篇 |
1972年 | 14630篇 |
1967年 | 12808篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
A. I. Belogorokhov I. I. Ivanchik S. V. Ponomarev D. R. Khokhlov E. I. Slyn’ko 《JETP Letters》1996,63(5):353-357
Selective photoconductivity at frequency ω=155 cm− was discovered in PbTe(Ga) narrow-gap semiconductors at liquid-nitrogen temperatures. The corresponding energy is much lower
than all characteristic energies of the electronic spectrum of the semiconductor. The effect is attributed to optical excitation
of a local vibrational mode of an impurity center leading to delocalization of the electrons.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 5, 342–346 (10 March 1996) 相似文献
995.
The capability of gated saturable absorbers for single-pulse selection is studied theoretically using the classical space-time-dependent rate-equation model. The dynamics of operation is followed experimentally by the well-known pump—probe technique. Comparing the theoretical and experimental results, it is found that gated saturable absorbers can efficiently be used for pulse forming and pulse selection of pulses longer than picosecond. 相似文献
996.
The applicability of differential electrolytic potentiometry as a detection system in flow injection analysis is investigated. A computer-controlled injector which delivers precise volumes of sample solutions in a reproducible manner was developed. Conditions such as current density employed, the concentrations of the solutions used and the flow rate were optimized. Chloride in water was determined by means of this system. The relation between chloride concentration and the measured signal was found to be Nernstian for solutions of concentrations above 6 μg ml−1 chloride. For solutions below this concentration, the relation is linear. 相似文献
997.
E. N. Yurchenko G. E. Kramareva N. G. Zubritskaya T. P. Gaidei 《Reaction Kinetics and Catalysis Letters》1995,55(2):425-432
In the Russian Scientific Center Applied Chemistry catalysts have been developed for the gas-phase fluorination of organics, including chlorine-containing substances, hydrogenation and reductive amination of organic substances, decomposition of liquid substances to gases, complete oxidation and reduction, suitable for environment at protection. 相似文献
998.
V. A. Nebol'sin B. M. Darinskii E. E. Popova A. A. Shchetinin 《Russian Physics Journal》1995,38(10):1023-1026
An estimate of the factors which influence the rate of growth of filamentary silicon crystals in a standard chloride system using a quartz reactor with hot walls is given. It is shown that a diffusion form of crystallization is observed under the conditions investigated.Voronezh State Technical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 22–26, October, 1995. 相似文献
999.
V. I. Storozhev 《Journal of Mathematical Sciences》1995,77(6):3514-3518
On the basis of the method of successive approximations in formal series we construct systems of particular solutions of the
equations of planar and flexural harmonic vibrations of thin rectilinear anisotropic plates with a plane of symmetry of elastic
properties parallel to the faces. The solutions constructed are classified as special sk-functions of generalized complex
variables.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika No. 24, 1993, pp. 54–61. 相似文献
1000.
F. G. Vagizov 《Hyperfine Interactions》1995,95(1):85-95
We present the results of an experimental investigation of a RF splitting of57Fe hyperfine lines in the regime of NMR and Mössbauer double resonance. The experiments have been performed as a function of RF field intensity and static magnetic field magnitude. The intensity of the RF components and the separation between them are extremely sensitive to the frequency and amplitude of the RF magnetic field. The RF splitting of hyperfine lines is inversely proportional to the strength of the static magnetic field. 相似文献