全文获取类型
收费全文 | 268618篇 |
免费 | 36037篇 |
国内免费 | 14232篇 |
专业分类
化学 | 182978篇 |
晶体学 | 2723篇 |
力学 | 15793篇 |
综合类 | 842篇 |
数学 | 35254篇 |
物理学 | 81297篇 |
出版年
2023年 | 6068篇 |
2022年 | 6355篇 |
2021年 | 8079篇 |
2020年 | 10253篇 |
2019年 | 8390篇 |
2018年 | 9122篇 |
2017年 | 7705篇 |
2016年 | 13987篇 |
2015年 | 12663篇 |
2014年 | 14136篇 |
2013年 | 17601篇 |
2012年 | 19715篇 |
2011年 | 17533篇 |
2010年 | 15281篇 |
2009年 | 14822篇 |
2008年 | 12097篇 |
2007年 | 11061篇 |
2006年 | 9568篇 |
2005年 | 11919篇 |
2004年 | 9990篇 |
2003年 | 7412篇 |
2002年 | 5547篇 |
2001年 | 4740篇 |
2000年 | 3776篇 |
1999年 | 3748篇 |
1998年 | 3409篇 |
1997年 | 3138篇 |
1996年 | 3224篇 |
1995年 | 2733篇 |
1994年 | 2709篇 |
1993年 | 2455篇 |
1992年 | 2374篇 |
1991年 | 2296篇 |
1990年 | 2064篇 |
1989年 | 1758篇 |
1988年 | 1581篇 |
1987年 | 1455篇 |
1986年 | 1361篇 |
1985年 | 1359篇 |
1984年 | 1290篇 |
1977年 | 1184篇 |
1976年 | 1427篇 |
1975年 | 1359篇 |
1974年 | 1430篇 |
1973年 | 1249篇 |
1972年 | 1261篇 |
1971年 | 1203篇 |
1970年 | 1280篇 |
1969年 | 1128篇 |
1968年 | 1179篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
A. P. Prudnikov Yu. A. Brychkov O. I. Marichev 《Journal of Mathematical Sciences》1991,54(6):1239-1341
Translated from Itogi Nauki i Tekhniki, Seriya Matematicheskii Analiz, Vol. 27, pp. 3–146, 1989. 相似文献
72.
The stressed state of a thick three-layer plate with two circular holes is studied. Resolving functions are expressed in terms of Kolosov-Muskhelishvili integral potentials and modified Bessel functions. The problem is reduced to solving an infinite set of linear algebraic equations.Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 18, pp. 25–28, 1987. 相似文献
73.
Dr. H. Schmieg Prof. Dr. P. Vielsack 《Archive of Applied Mechanics (Ingenieur Archiv)》1987,57(6):446-458
Übersicht Betrachtet wird ein zwangserregtes Zweikörpersystem mit wechselnden Bindungen infolge trockener Reibung. Stationäre Bewegungen werden als Grenzfall instationärer Einschwingvorgänge berechnet. Abhängig von den Systemparametern ergeben sich drei typische Bewegungsformen. Ihnen entsprechen dauernde Haftzustände, wechselnde Haft-Gleitzustände oder dauernde Gleitzustände an der Berührfläche beider Körper.
Intermittant constraints in a two-body-system with dry friction
Summary An externally excited two-body-system with intermittant constraints due to dry friction is considered. Stationary motions are calculated as limit cases of instationary transients. Depending on the parameters of the system, three typical modes are of interest. These correspond to permanent sticking, slipstick behaviour, or to permanent slipping in the contact surface of the bodies, respectively.相似文献
74.
D. Yu. Gladilov S. Yu. Nekhaevskii A. V. Ochkin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(12):1934-1939
Various methods for describing the distribution of water in the H2O-tributyl phosphate (TBP) system were considered. An equation for describing the deviations from the Henry law was proposed. A three-parameter equation for calculating the distribution of water in H2O-TBP-solvent systems was derived. It is based on the additive solubility model and allows for the dependence of the activity coefficients on the TBP concentration. Based on the published data, the parameters of the equation for a number of systems were calculated. 相似文献
75.
Note on Bernstein polynomials and Kantorovich polynomials 总被引:2,自引:0,他引:2
Wang Xiaochun 《分析论及其应用》1991,7(2):99-105
We obtain two asymptotic representations of remainder of approximation of derivable functions by Bernstein polynomials and
Kantorovich polynomials separately. 相似文献
76.
Ronggang Wang 《Communications in Mathematical Physics》1991,137(3):587-597
A new type of vortices called Chern-Simons vortices is considered and the existence is established. 相似文献
77.
Wen Zhang Hui Huang Yu Ding Margherita Gavagnin Ernesto Mollo Guido Cimino Yue‐Wei Guo 《Helvetica chimica acta》2006,89(4):813-820
Three new polyoxygenated steroids, muricesteroid ( 1 ), and menellsteroids A ( 2 ) and B ( 3 ), were isolated from two species of the South China Sea gorgonian Muricella flexuosa and Menella verrucosa Brundin , respectively. The structures of these new compounds were elucidated on the basis of extensive spectroscopic analysis, chemical methods and comparison with known related compounds. 相似文献
78.
79.
In a two-dimensional array of magnetic moments with planar magnetization and relatively weak anisotropy in the basal plane, a stepwise phase transition is induced by an external magnetic field parallel to the easy axis of the system. This transition is similar to the spin flop phase transition in weakly anisotropic Heisenberg antiferromagnets with the significant difference that it is accompanied by the rearrangement of the sublattice structure of the magnet; i.e., it can be interpreted as a topological transition. The transition should manifest itself for arrays of submicron magnetic particles (magnetic dots) on nonmagnetic substrates, which have recently become the object of intensive research. 相似文献
80.
Yu. M. Smirnov 《Journal of Applied Spectroscopy》2006,73(6):785-791
Dissociative excitation of the lead atom in e-PbI2 collisions has been studied experimentally. 27 excitation cross sections were measured for an energy of the exciting electrons
equal to 100 eV. Nine optical excitation functions were recorded with variation of the electron energy in the range 0–100
eV. The most probable reaction channels for low electron energies are discussed, as well as the ratio of the dissociative
excitation cross sections for the lead atom in e-PbI2 and e-PbCl2 collisions.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 701–706, November–December, 2006. 相似文献