全文获取类型
收费全文 | 2034篇 |
免费 | 11篇 |
国内免费 | 2篇 |
专业分类
化学 | 1051篇 |
晶体学 | 24篇 |
力学 | 52篇 |
数学 | 182篇 |
物理学 | 738篇 |
出版年
2021年 | 40篇 |
2020年 | 26篇 |
2019年 | 39篇 |
2018年 | 43篇 |
2017年 | 51篇 |
2016年 | 70篇 |
2015年 | 28篇 |
2014年 | 48篇 |
2013年 | 82篇 |
2012年 | 68篇 |
2011年 | 91篇 |
2010年 | 80篇 |
2009年 | 74篇 |
2008年 | 86篇 |
2007年 | 78篇 |
2006年 | 64篇 |
2005年 | 61篇 |
2004年 | 55篇 |
2003年 | 48篇 |
2002年 | 56篇 |
2001年 | 43篇 |
2000年 | 40篇 |
1999年 | 38篇 |
1998年 | 20篇 |
1997年 | 27篇 |
1996年 | 22篇 |
1995年 | 19篇 |
1994年 | 26篇 |
1993年 | 20篇 |
1992年 | 31篇 |
1991年 | 21篇 |
1990年 | 26篇 |
1989年 | 22篇 |
1988年 | 23篇 |
1987年 | 29篇 |
1986年 | 21篇 |
1983年 | 20篇 |
1982年 | 22篇 |
1980年 | 21篇 |
1979年 | 18篇 |
1978年 | 36篇 |
1977年 | 22篇 |
1976年 | 18篇 |
1975年 | 24篇 |
1974年 | 26篇 |
1973年 | 21篇 |
1972年 | 18篇 |
1971年 | 18篇 |
1968年 | 20篇 |
1967年 | 18篇 |
排序方式: 共有2047条查询结果,搜索用时 8 毫秒
941.
942.
S. V. Safronov A. A. Pavlov V. I. Sokolov A. A. Koridze 《Russian Chemical Bulletin》2018,67(2):255-259
The reaction of the divalent ruthenium complexes [CpFRuCl]n and [CpFRu(MeCN)3]PF6 with substituted pentafulvenes 1,2-(Me2NCH)(CO2Et)C5H3 and 1,3-(Me2NCH)(CO2Et)- C5H3 followed by hydrolysis affords new homoannular disubstituted ruthenocenes {1,2- (CO2Et)(CHO)C5H3}RuCpF and {1,3-(CO2Et)(CHO)C5H3}RuCpF (CpF = C5Me4CF3), re- spectively. 相似文献
943.
V. S. Korenev P. A. Abramov M. N. Sokolov 《Russian Journal of Inorganic Chemistry》2018,63(5):604-609
Polymolybdates of the composition Cs2Mo4O13 (1) and Cs4Mo8O26 · 4H2O (2) are synthesized under hydrothermal conditions from a mixture containing (NH4)6Mo7O24 · 4H2O and CsCl at pH 2.5 and 3.6, respectively. 相似文献
944.
Viacheslav I.Sokolov 《有机化学》2018,(1)
近年研究表明二茂铁的环钯化衍生物被广泛地应用于各类偶联反应中,比如Heck反应、Suzuki反应、aza-Claisen重排反应等.主要综述了含氮导向基的二茂铁衍生物的环钯化反应,包括通过不对称诱导或拆分手段合成具有平面手性环钯化合物,基于环金属化反应1,1'-取代二茂铁钯化物的合成,以及其在催化反应的应用. 相似文献
945.
The classical factorization method reduces the study of a system of ordinary differential equations Ut=[U+, U] to solving algebraic equations. Here U(t) belongs to a Lie algebra
which is the direct sum of its subalgebras
and
, where “+” signifies the projection on
. We generalize this method to the case
. The corresponding quadratic systems are reducible to a linear system with variable coefficients. It is shown that the generalized
version of the factorization method can also be applied to Liouville equation-type systems of partial differential equations.
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 110, No. 3, pp. 339–350, March, 1997. 相似文献
946.
S. E. Tkachenko A. N. Pushin V. B. Sokolov V. M. Fedoseev I. V. Martynov 《Chemistry of Heterocyclic Compounds》1998,34(3):347-350
A convenient method is proposed for obtaining difficultly available derivatives of 2-amino-5-chloromethyl-2-thiazoline by the cyclization of N-allythioureas under the action of-chloronitrosoalkanes. It is assumed that the reaction proceeds as a halogenophilic process leading to the intermediate formamidinesulfenyl chloride which is rapidly and selectively cyclized with the formation of 2-amino-2-thiazoline derivatives.Institute of Physiologically Active Substances, Russian Academy of Sciences, Chernogolovka 142432, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 381–384, March, 1998. 相似文献
947.
948.
A model of magnetic field generation by the turbulent motions of a highly conducting fluid is constructed. It is assumed that the field is generated in individual cells of space in a statistically independent manner. A coupling between the cells is realized by magnetic diffusion. The rates of growth of the field and its moments are calculated. The field distribution generated by this mechanism possesses an intermittent nature in both time and space. 相似文献
949.
J. Brunner H. J. Grabosch H. H. Kaufmann R. Nahnhauer S. Nowak H. E. Roloff S. Schlenstedt V. V. Ammosov A. A. Ivanilov P. V. Ivanov V. I. Konyushko V. M. Korablev V. A. Korotkov V. V. Makeev A. G. Myagkov A. Yu. Polyarush A. A. Sokolov SKAT Collaboration 《Zeitschrift fur Physik C Particles and Fields》1989,42(3):361-365
Using the freon filled bubble chamber SKAT at the Serpukhov accelerator we study event charge distributions in neutrino and antineutrino charged current reactions in the (anti)neutrino energy region from 3–30 GeV. We derive from the data the total cross section ratios of reactions on neutrons to reactions on protonsR ν=2.24±0.18 and \(R_{\bar v} = 0.43\) in agreement with the predictions of the quark parton model. These values agree also with other experimental results at different energies. For neutrino reactions we study additionally the differential distributions in Bjorken variablesx andy. 相似文献
950.
A. Kisliuk V. N. Novikov A. P. Sokolov 《Journal of Polymer Science.Polymer Physics》2002,40(2):201-209
The polarized (VV) and depolarized (VH) light scattering spectra of polyisobutylene, poly(methyl methacrylate), and glycerol were measured in the gigahertz frequency range at temperatures below and above the glass transition. Both VV and VH spectra exhibit a significant constant loss contribution that appears as a frequency‐independent imaginary part of the susceptibility spectrum. Existence of the frequency‐independent susceptibility in VV spectra below the Brillouin lines suggests that the constant loss also appears in mechanical relaxation in the gigahertz frequency range. Intensity of the constant loss increases strongly with temperature. Analysis of the spectra and literature data suggests that the constant loss can be general for many glass‐forming systems, but it is hidden in many cases by other relaxation contributions. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 201–209, 2002 相似文献