全文获取类型
收费全文 | 298413篇 |
免费 | 1348篇 |
国内免费 | 329篇 |
专业分类
化学 | 136989篇 |
晶体学 | 4651篇 |
力学 | 16881篇 |
综合类 | 3篇 |
数学 | 42154篇 |
物理学 | 99412篇 |
出版年
2021年 | 3108篇 |
2020年 | 3418篇 |
2019年 | 4195篇 |
2018年 | 6229篇 |
2017年 | 6449篇 |
2016年 | 7950篇 |
2015年 | 3527篇 |
2014年 | 6889篇 |
2013年 | 12135篇 |
2012年 | 10132篇 |
2011年 | 11805篇 |
2010年 | 9994篇 |
2009年 | 10153篇 |
2008年 | 11411篇 |
2007年 | 11209篇 |
2006年 | 9976篇 |
2005年 | 8611篇 |
2004年 | 8370篇 |
2003年 | 7769篇 |
2002年 | 8054篇 |
2001年 | 7667篇 |
2000年 | 6059篇 |
1999年 | 4492篇 |
1998年 | 4264篇 |
1997年 | 4127篇 |
1996年 | 3738篇 |
1995年 | 3297篇 |
1994年 | 3360篇 |
1993年 | 3374篇 |
1992年 | 3384篇 |
1991年 | 3786篇 |
1990年 | 3787篇 |
1989年 | 3797篇 |
1988年 | 3545篇 |
1987年 | 3629篇 |
1986年 | 3322篇 |
1985年 | 3851篇 |
1984年 | 4083篇 |
1983年 | 3490篇 |
1982年 | 3689篇 |
1981年 | 3374篇 |
1980年 | 3133篇 |
1979年 | 3621篇 |
1978年 | 3686篇 |
1977年 | 3855篇 |
1976年 | 3930篇 |
1975年 | 3671篇 |
1974年 | 3527篇 |
1973年 | 3688篇 |
1972年 | 3177篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
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
22.
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
23.
The radiation emitted by charged, scalar particles in a Schwarzschild field with maximal acceleration corrections is calculated classically and in the tree approximation of quantum field theory. In both instances the particles emit radiation that has characteristics similar to those of gamma-ray bursters. 相似文献
24.
V. Palyok I.A. Szabó D.L. Beke A. Kikineshi 《Applied Physics A: Materials Science & Processing》2002,74(5):683-687
Surface relief formation at holographic recording on amorphous selenium films was demonstrated and investigated. The presence
of this optical phase modulation component is essential for ensuring significant, stable and erasable optical recording in
a-Se films at 290–320 K temperatures, where conventional photodarkening was known as insignificant and unstable. Photocrystallization
can only be observed in super-exposed a-Se films at the given experimental conditions of hologram recording. Erasing behavior
of surface relief gratings under heat treatment was also investigated in order to reveal further details of the mechanism.
Photoinduced structural transformations within the amorphous phase, connected to local ordering under the condition of light-induced
fluidity, are proposed as an explanation for the relief formation and erasing. The observed reversible optical recording process
may be useful for the various optoelectronic applications of photoconductive a-Se layers.
Received: 12 June 2000 / Accepted: 6 June 2001 / Published online: 30 August 2001 相似文献
25.
D. V. Vyalykh A. M. Shikin G. V. Prudnikova A. Yu. Grigor’ev A. G. Starodubov V. K. Adamchuk 《Physics of the Solid State》2002,44(1):164-170
This paper reports on the first experimental observation of quantum-well states and sp-type resonances in thin single-crystal gold, silver, and copper layers formed on single-crystal W(110) surfaces, which result from spatial localization of Bloch-type electronic wave functions in a quantum well with potential barriers at the vacuum/metal and metal/W(110) interfaces. The quantization of the valence-band electronic structure in Au/W(110), Ag/W(110), and Cu/W(110) systems was studied experimentally using angle-resolved photoelectron spectroscopy. 相似文献
26.
Yu. V. Borovskikh 《Journal of Mathematical Sciences》1991,53(4):353-358
Estimates of a rate of convergence of orderO(n
–1) are obtained for integral functionals of an empirical process.Translated fromTeoriya Sluchainykh Protsessov, Vol. 15, pp. 10–16, 1987. 相似文献
27.
V. Yu. Korolev 《Journal of Mathematical Sciences》1991,57(4):3270-3277
Translated fromProblemy Ustoichivosti Stokhasticheskikh Modelei. Trudy Seminara, 1988, pp. 84–92. 相似文献
28.
V. O. Tarasov 《Journal of Mathematical Sciences》1991,54(3):958-967
A mixed boundary-value problem for the nonlinear Schrödinger equation and its generalization is studied by the method used for the inverse scattering problem. A connection is established between conservation laws and boundary conditions in integrable boundary-value problems for higher nonlinear Schrödinger equations. It is shown that the generalized boundary-value problem requires a joint consideration of regular and singular solutions for the nonlinear Schrödinger equation with repulsion.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 169, pp. 151–165, 1988. 相似文献
29.
V. L. Topunov 《Acta Appl Math》1989,16(2):191-206
In this paper, an application of the Riquer-Thomas-Janet theory is described for the problem of transforming a system of partial differential equations into a passive form, i.e., to a special form which contains explicitly both the equations of the initial system and all their nontrivial differential consequences. This special representation of a system markedly facilitates the subsequent integration of the corresponding differential equations. In this paper, the modern approach to the indicated problem is presented. This is the approach adopted in the Knuth-Bendix procedure [13] for critical-pair/completion and then Buchberger's algorithm for completion of polynomial ideal bases [13] (or, alternatively, for the construction of Groebner bases for ideals in a differential operator ring [14]). The algorithm of reduction to the passive form for linear system of partial differential equations and its implementation in the algorithmic language REFAL, as well as the capabilities of the corresponding program, are outlined. Examples illustrating the power and efficiency of the system are presented. 相似文献
30.