全文获取类型
收费全文 | 28376篇 |
免费 | 359篇 |
国内免费 | 69篇 |
专业分类
化学 | 13552篇 |
晶体学 | 453篇 |
力学 | 1003篇 |
综合类 | 11篇 |
数学 | 3798篇 |
物理学 | 9987篇 |
出版年
2023年 | 32篇 |
2022年 | 251篇 |
2021年 | 456篇 |
2020年 | 450篇 |
2019年 | 640篇 |
2018年 | 1074篇 |
2017年 | 1168篇 |
2016年 | 1496篇 |
2015年 | 662篇 |
2014年 | 1289篇 |
2013年 | 1925篇 |
2012年 | 1832篇 |
2011年 | 1886篇 |
2010年 | 1986篇 |
2009年 | 1942篇 |
2008年 | 1951篇 |
2007年 | 1868篇 |
2006年 | 1625篇 |
2005年 | 1087篇 |
2004年 | 832篇 |
2003年 | 473篇 |
2002年 | 507篇 |
2001年 | 397篇 |
2000年 | 719篇 |
1999年 | 400篇 |
1998年 | 472篇 |
1997年 | 450篇 |
1996年 | 145篇 |
1995年 | 63篇 |
1994年 | 50篇 |
1993年 | 35篇 |
1992年 | 58篇 |
1991年 | 43篇 |
1990年 | 28篇 |
1989年 | 20篇 |
1988年 | 23篇 |
1987年 | 24篇 |
1986年 | 24篇 |
1985年 | 45篇 |
1984年 | 34篇 |
1983年 | 20篇 |
1982年 | 26篇 |
1981年 | 34篇 |
1980年 | 18篇 |
1979年 | 35篇 |
1978年 | 27篇 |
1977年 | 28篇 |
1976年 | 21篇 |
1974年 | 22篇 |
1968年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
M. G. Voronkov S. G. D’yachkova I. P. Lebedeva A. V. Evart L. G. Shagun 《Russian Journal of General Chemistry》2007,77(4):604-606
Alkylthiochloroacetylenes react with geminal (in ether) and vicinal (in THF) dithiols to form, respectively, functional 1,3-dithiolenes (yield 43%) or 1,3-dithiolanes (yield 34%). 相似文献
172.
173.
M. S. Nikol’skii 《Computational Mathematics and Modeling》2007,18(4):420-431
We consider the behavior of bundles of optimal controls when the initial state of the system goes to some given vector. We
investigate three types of optimization problems: problems with fixed process length and a free right endpoint; problems with
fixed process length and a fixed right endpoint; time-optimal problems. The article is a review of recent results obtained
by the author.
__________
Translated from Nelineinaya Dinamika i Upravlenie, No. 4, pp. 301–314, 2004. 相似文献
174.
N. N. Koval’ Yu. F. Ivanov I. M. Goncharenko O. V. Krysina Yu. A. Kolubaeva K. A. Koshkin 《Russian Physics Journal》2007,50(2):146-152
Phase composition, defect substructure, and mechanical properties of the Ti-Si-N coating deposited on metal and ceramic-metal substrates by electroarc sputtering of the Ti-Si composite cathode in an ionized
nitrogen atmosphere are investigated by the methods of modern materials science. It is established that coatings so formed
with a thickness of ∼1–3 μm are superhard (Hv ∼ 50 GPa), and have the nanocrystalline structure (with crystalline sizes D = 7 nm) based on titanium nitride δ-TiN.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 46–51, February, 2007. 相似文献
175.
Victor V. Dodonov Margarita A. Man’ko Vladimir I. Man’ko Apostol Vourdas 《Journal of Russian Laser Research》2007,28(5):404-428
A brief review of the history of ten workshops/conferences on “Squeezed States and Uncertainty Relations” and main achievements
in the related fields of quantum physics for the period from 1991 to 2007 are presented. 相似文献
176.
E. S. Zhukova A. S. Prokhorov I. E. Spektor V. A. Karavanskiĭ N. N. Mel’nik T. N. Zavaritskaya B. P. Gorshunov 《Physics of the Solid State》2007,49(12):2242-2250
The dielectric response (conductivity and permittivity) spectra of a series of nanoporous silicon samples prepared by anodization of low-resistivity single-crystal silicon are measured, for the first time, using terahertz and IR spectroscopy in the frequency range 7–4000 cm?1 at room temperature. The spectra obtained are analyzed in terms of the effective medium theory with a size-dependent dielectric response function of nanoinclusions and averaged dielectric characteristics of the surrounding medium. The geometric and dielectric characteristics of silicon nanoinclusions are determined. The dielectric properties of inclusions are found to be affected by nanosize effects, namely, carrier scattering at crystallite boundaries and a broadening of the band gap due to quantum confinement. The spectra of the samples prepared by adding iodine to the electrolyte exhibit a resonance at frequencies of 150–300 cm?1. The nature of the resonance can be associated with the presence of chemisorbed iodine on the surface of porous silicon. Possible mechanisms responsible for the changes in broadband conductivity and permittivity spectra of single-crystal silicon upon transformation into a nanoporous structure are discussed. 相似文献
177.
A. V. Porfir’eva G. A. Evtyugin E. Yu. Podshivalina L. I. Anchikova G. K. Budnikov 《Journal of Analytical Chemistry》2007,62(12):1180-1186
A new technique is proposed for detecting interactions between DNA and DNA autoimmune antibodies using a potentiometric sensor based on a glassy-carbon electrode modified with polyaniline and native DNA from chicken erythrocytes. It is shown that the DNA-antibody interaction changes the rate of polyaniline doping in transferring the DNA sensor from an alkaline (pH 7.5) solution, which is optimum for the immunochemical reaction, to an acidic (pH 3.0) solution. The dynamics of the variation of the DNA sensor potential depends on the titer of antibodies and their origin. The dependence of the DNA sensor signal on the dilution of the blood sera from systemic lupus erythematosus and autoimmune thyroiditis patients shows that DNA antibodies can be diagnosed by the characteristic maximum in the dilution curve found in the range of serum dilutions from 1: 20 to 1: 50. 相似文献
178.
R. A. Vikent’ev 《Siberian Mathematical Journal》2007,48(3):428-429
In the automorphism group of a rank 3 free group we find two nonconjugate automorphisms whose mapping tori are isomorphic groups. 相似文献
179.
D. A. Kosmodem’yanskii 《Moscow University Mathematics Bulletin》2007,62(2):56-60
Spectral properties of the following three homogenized problems in the mechanics of strongly nonhomogeneous media are considered: the “double porosity” problem, the oscillation problem for a mixture of two viscous compressible liquids, and the oscillation of a medium consisting of an elastic frame and a viscous liquid. For all three cases results on the structure of the spectrum and on the existence of so-called “spectral gaps” are obtained. 相似文献
180.
O. V. Il’in 《Journal of Mathematical Sciences》2007,141(1):1041-1047
We describe W-geometry of two-dimensional Toda systems associated with the Lie algebra C
n
.
__________
Translated from Fundamental’naya i Prikladnaya Matematika (Fundamental and Applied Mathematics), Vol. 11, No. 1, Geometry,
2005. 相似文献