全文获取类型
收费全文 | 465979篇 |
免费 | 3903篇 |
国内免费 | 1625篇 |
专业分类
化学 | 229866篇 |
晶体学 | 6889篇 |
力学 | 23920篇 |
综合类 | 63篇 |
数学 | 63330篇 |
物理学 | 147439篇 |
出版年
2020年 | 4648篇 |
2019年 | 5402篇 |
2018年 | 7685篇 |
2017年 | 7873篇 |
2016年 | 10314篇 |
2015年 | 5360篇 |
2014年 | 9356篇 |
2013年 | 19049篇 |
2012年 | 16034篇 |
2011年 | 19170篇 |
2010年 | 14864篇 |
2009年 | 14856篇 |
2008年 | 18229篇 |
2007年 | 18043篇 |
2006年 | 16529篇 |
2005年 | 14677篇 |
2004年 | 13670篇 |
2003年 | 12403篇 |
2002年 | 12541篇 |
2001年 | 12921篇 |
2000年 | 10031篇 |
1999年 | 7391篇 |
1998年 | 6606篇 |
1997年 | 6473篇 |
1996年 | 6091篇 |
1995年 | 5351篇 |
1994年 | 5505篇 |
1993年 | 5389篇 |
1992年 | 5637篇 |
1991年 | 5997篇 |
1990年 | 5805篇 |
1989年 | 5720篇 |
1988年 | 5457篇 |
1987年 | 5399篇 |
1986年 | 5177篇 |
1985年 | 6443篇 |
1984年 | 6693篇 |
1983年 | 5671篇 |
1982年 | 6011篇 |
1981年 | 5575篇 |
1980年 | 5153篇 |
1979年 | 5767篇 |
1978年 | 5972篇 |
1977年 | 6140篇 |
1976年 | 6257篇 |
1975年 | 5798篇 |
1974年 | 5736篇 |
1973年 | 5944篇 |
1972年 | 4825篇 |
1971年 | 4161篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
V. V. Tokarchuk 《Journal of Applied Mathematics and Mechanics》1989,53(6):708-715
The Langevin dynamics and fluctuational-dissipative relationships for the hydrodynamic fluctuations for systems which are described in the third Barnett order with respect to the gradients of the hydrodynamic variables are generalized on the basis of a kinetic approach. 相似文献
92.
93.
94.
The acoustic field inside a shell excited by a spatially inhomogeneous harmonic pressure field is studied. The shell is assumed
to have a finite length, a set of orthogonal stiffening ribs, two ends bounding the acoustic volume, and a sound-insulating
structure, which includes layers of sound-insulating material, resonant elements, and an interior panel. The shell is considered
to be orthotropic with boundary conditions corresponding to a free support. For the acoustic field in the closed volume, analytical
expressions are derived with allowance for the elastoacoustic interaction of the shell with the sound-insulating layers and
with the medium both inside the shell (with arbitrary impedance values at the ends) and outside it. These expressions are
used to investigate the effect of different types of resonant systems on the sound field inside the shell. 相似文献
95.
V. I. Korobov 《Few-Body Systems》2002,31(2-4):133-138
In this contribution we consider a phenomenon of metastable states in antiprotonic helium atoms, precise spectroscopy of
these states and a present-day study of the electromagnetic properties of antiprotons.
Received October 16, 2001; accepted for publication November 13, 2001 相似文献
96.
The effect of hydrogen on the photoluminescence and planar conductivity of GaAs/InGaAs quantum-well heterostructures with an island Pd layer at the anodically oxidized surface was studied. Unlike continuous deposited Pd layers, island layers do not cause the formation of defects in the GaAs surface region and yet the Pd layer maintains high catalytic activity with respect to hydrogen. It is found that the thermal treatment of such a structure in a hydrogen atmosphere causes atomic-hydrogen passivation of the defects in quantum wells. Studies of the characteristics of planar photoresistors with an island Pd layer acting as hydrogen sensors show that their hydrogen detectivity is approximately two orders of magnitude higher than that of diode structures with continuous Pd layers. 相似文献
97.
V. Čápek 《Czechoslovak Journal of Physics》1991,41(10):975-989
A review of ideas leading to full rejection of any finite or partially-infinite order kinetic equation linearized in external field is given on grounds of the time-convolution Generalized Master Equations (GME). By two examples (two-level and band conduction problem), it is shown how standard kinetic equations result from GME in the lowest order approximations which obscure, however, a direct correspondence with the Kubo linear response theory. Without approximations, on the other hand, the rigorous approach is shown to be fully equivalent with the Kubo results. It is argued and illustrated that usual technical simplicity and seeming physical lucidity of standard theories (connected with the presence of field-independent transfer or scattering rates in the fielddependent linearized theory) are just owing to structural features which are solely due to the lowest order approximations involved. These features (i.e. also the possibility of standard physical interpretation of kinetic phenomena) are proved to disappear completely as far as the theory goes properly to higher orders. 相似文献
98.
99.
V. A. Artamonov 《Journal of Mathematical Sciences》1991,57(2):2959-3009
A survey of the development of the theory of universal algebras in the years 1976–1988. Such basic directions of development of this theory as classes of universal algebras (varieties, quasivarieties, etc.), Mal'tsev conditions, congruences, sheaves, homomorphisms, subalgebras, products of algebras, clones of operations, completeness, systems of equations in algeberas, and connections with computer mathematics show up in it. Considerable attention is given to concrete classes of algebras (p-algebras, BCK-algebras, unary algebras, etc.).Translated from Itogi Nauki i Tekhniki, Seriya Algebra, Topologiya, Geometriya, Vol. 27, pp. 45–124, 1989. 相似文献
100.
A. L. Chistov 《Journal of Mathematical Sciences》2006,138(3):5733-5752
Consider a projective algebraic variety W which is an irreducible component of the set of all common zeros of a family of
homogeneous polynomials of degrees less than d in n + 1 variables over a field of zero characteristic. Consider a dominant
rational morphism from W to W′ given by homogeneous polynomials of degree d′. We suggest algorithms for constructing objects
in general position related to this morphism. They generalize some algorithms from the first part of the paper to the case
dim W > dim W′. These algorithms are deterministic and polynomial in (dd′)n and the size of the input. Bibliography: 12 titles.
__________
Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 325, 2005, pp. 181–224. 相似文献