全文获取类型
收费全文 | 10296篇 |
免费 | 328篇 |
国内免费 | 2篇 |
专业分类
化学 | 5352篇 |
晶体学 | 78篇 |
力学 | 186篇 |
数学 | 2068篇 |
物理学 | 2942篇 |
出版年
2021年 | 148篇 |
2020年 | 140篇 |
2019年 | 128篇 |
2018年 | 199篇 |
2017年 | 222篇 |
2016年 | 466篇 |
2015年 | 308篇 |
2014年 | 353篇 |
2013年 | 800篇 |
2012年 | 485篇 |
2011年 | 620篇 |
2010年 | 400篇 |
2009年 | 342篇 |
2008年 | 318篇 |
2007年 | 273篇 |
2006年 | 203篇 |
2005年 | 161篇 |
2004年 | 156篇 |
2003年 | 157篇 |
2002年 | 167篇 |
2001年 | 137篇 |
2000年 | 128篇 |
1999年 | 138篇 |
1998年 | 129篇 |
1997年 | 121篇 |
1996年 | 121篇 |
1995年 | 114篇 |
1994年 | 110篇 |
1993年 | 116篇 |
1992年 | 110篇 |
1991年 | 97篇 |
1990年 | 102篇 |
1989年 | 97篇 |
1988年 | 94篇 |
1987年 | 118篇 |
1986年 | 86篇 |
1985年 | 121篇 |
1984年 | 127篇 |
1983年 | 118篇 |
1982年 | 108篇 |
1981年 | 111篇 |
1980年 | 110篇 |
1979年 | 120篇 |
1978年 | 118篇 |
1977年 | 113篇 |
1976年 | 112篇 |
1975年 | 94篇 |
1974年 | 101篇 |
1973年 | 102篇 |
1966年 | 82篇 |
排序方式: 共有10000条查询结果,搜索用时 420 毫秒
71.
A.V. Andreev B. Janoušová V. Sechovský Y. Homma Y. Shiokawa 《Czechoslovak Journal of Physics》2002,52(2):275-278
We present the first single-crystal study of Fe and Ni doped U(Co1-x
T
x
)Al compounds in comparison to the parent compound, the itinerant 5f-electron metamagnet UCoAl. Magnetization and specific-heat data measured in the temperature range of (1.8-300) K and in fields up to 10 T are analyzed and discussed. Both compounds exhibit a strong uniaxial anisotropy with the dominating magnetic response along the c-axis of the hexagonal ZrNiAl-type structure. Ni substitution yields an increase of the critical field for metamagnetism; UCo0.95Fe0.05Al is ferromagnetic below 30 K. Temperature evolution of the entropy change between 0 and 10 T points to involvement of magnetic correlations or spin fluctuations in the paramagnetic compounds UCoAl and UCo0.95Ni0.05Al. 相似文献
72.
73.
Dragan DJURCIC Aleksandar TORGASEV 《数学学报(英文版)》2006,22(3):689-692
In this paper, we prove some properties of the Seneta sequences and functions, and in particular we prove a representation theorem in the Karamata sense for the sequences from the Seneta class SOc. 相似文献
74.
A separation of the vibrational-electronic Hamiltonian in crude representation is presented. The separation is done in the following way: first we quantize only the electronic states on the unperturbed Hamiltonian level, then using the perturbation theory, we treat the terms where we have electronic operators to obtain new harmonic potential energy. Then we quantize a-posteriori the nuclear motion and as a result the only perturbation term is due to anharmonicity. 相似文献
75.
76.
Marston Conder Aleksander Malnič Dragan Marušič Primž Potočnik 《Journal of Algebraic Combinatorics》2006,23(3):255-294
A list is given of all semisymmetric (edge- but not vertex-transitive) connected finite cubic graphs of order up to 768. This
list was determined by the authors using Goldschmidt's classification of finite primitive amalgams of index (3,3), and a computer
algorithm for finding all normal subgroups of up to a given index in a finitely-presented group. The list includes several
previously undiscovered graphs. For each graph in the list, a significant amount of information is provided, including its
girth and diameter, the order of its automorphism group, the order and structure of a minimal edge-transitive group of automorphisms,
its Goldschmidt type, stabiliser partitions, and other details about its quotients and covers. A summary of all known infinite
families of semisymmetric cubic graphs is also given, together with explicit rules for their construction, and members of
the list are identified with these. The special case of those graphs having K1,3 as a normal quotient is investigated in detail.
Supported in part by N.Z. Marsden Fund (grant no. UOA 124) and N.Z. Centres of Research Excellence Fund (grant no. UOA 201)
Supported in part by “Ministrstvo za šolstvo, znanost in šport Slovenije”, research program no. 101-506.
Supported in part by research projects no. Z1-4186-0101 and no. Z1-3124-0101. The fourth author would like to thank the University
of Auckland for hospitality during his visit there in 2003. 相似文献
77.
Lubomír Kubáček 《Mathematica Slovaca》2007,57(1):59-82
In some situations estimates of unknown parameters must be corrected by additional measurements. It is in principle no problem
to calculate the corrected estimates, however, it is of more interest to find formulae for correction itself. The formulae
enable us to design an additional experiment and to judge its usefulness.
The aim of the paper is to find such formulae for several situations.
Supported by the grant of the Council of Czech Government MSM 6 198 959 214. 相似文献
78.
Gašper Jaklič Jernej Kozak Marjeta Krajnc Vito Vitrih Emil Žagar 《Numerical Algorithms》2007,45(1-4):49-60
In this paper, three-pencil lattices on triangulations are studied. The explicit representation of a lattice, based upon barycentric
coordinates, enables us to construct lattice points in a simple and numerically stable way. Further, this representation carries
over to triangulations in a natural way. The construction is based upon group action of S
3 on triangle vertices, and it is shown that the number of degrees of freedom is equal to the number of vertices of the triangulation.
相似文献
79.
The stoichiometric reactions of trimethylaluminum with 2,6‐(MeOCH2)2C6H3OH (LH) revealed compounds L3Al ( 1 ) and L2AlMe ( 2 ). On the other hand reaction of 1 equiv. of LH with trimethylaluminum did not lead to the formation of complex LAlMe2 ( 3 ), rather 2 together with Me3Al were observed as a result of a disproportionation of 3 . Compounds 1 and 2 were characterized by elemental analysis, 1H and 13C NMR spectroscopy and in the case of 1 by X‐ray diffraction. Derivative 2 underwent transmetalation with Ph3SnOH, giving LSnPh3 ( 4 ) as the result of a migration of ligand L from the aluminum to the tin atom. The identity of 4 was established by elemental analysis, 1H, 13C and 119Sn NMR spectroscopy and 1H, 119Sn HMBC experiments. The system 2 and B(C6F5)3 in a 1:1 molar ratio was shown to be active in the polymerization of propylene oxide and ε‐caprolactone. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
80.
Abull is the (self-complementary) graph with verticesa, b, c, d, e and edgesab, ac, bc, bd, ce; a graphG is calledBerge if neitherG not its complement contains a chordless cycle whose length is odd and at least five. We prove that bull-free Berge graphs are perfect; a part of our argument relies on a new property of minimal imperfect graphs.This work was done while both authors were at the School of Computer Science, McGill University; support by NSERC is gratefully acknowledged. 相似文献