全文获取类型
收费全文 | 86715篇 |
免费 | 550篇 |
国内免费 | 384篇 |
专业分类
化学 | 28786篇 |
晶体学 | 862篇 |
力学 | 6944篇 |
综合类 | 1篇 |
数学 | 33849篇 |
物理学 | 17207篇 |
出版年
2021年 | 98篇 |
2020年 | 125篇 |
2019年 | 123篇 |
2018年 | 10560篇 |
2017年 | 10379篇 |
2016年 | 6347篇 |
2015年 | 1085篇 |
2014年 | 611篇 |
2013年 | 1046篇 |
2012年 | 4252篇 |
2011年 | 11030篇 |
2010年 | 5929篇 |
2009年 | 6324篇 |
2008年 | 6970篇 |
2007年 | 9110篇 |
2006年 | 604篇 |
2005年 | 1566篇 |
2004年 | 1775篇 |
2003年 | 2158篇 |
2002年 | 1216篇 |
2001年 | 399篇 |
2000年 | 419篇 |
1999年 | 250篇 |
1998年 | 287篇 |
1997年 | 225篇 |
1996年 | 285篇 |
1995年 | 192篇 |
1994年 | 146篇 |
1993年 | 159篇 |
1992年 | 144篇 |
1991年 | 130篇 |
1990年 | 129篇 |
1989年 | 144篇 |
1988年 | 141篇 |
1987年 | 133篇 |
1986年 | 131篇 |
1985年 | 151篇 |
1984年 | 141篇 |
1983年 | 137篇 |
1982年 | 132篇 |
1981年 | 110篇 |
1980年 | 133篇 |
1979年 | 122篇 |
1978年 | 147篇 |
1977年 | 104篇 |
1976年 | 112篇 |
1975年 | 96篇 |
1974年 | 98篇 |
1973年 | 89篇 |
1972年 | 69篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
21.
22.
Balázs Szendröi 《Mathematische Zeitschrift》2002,240(2):233-241
This note shows that a certain toric quotient of the quintic Calabi-Yau threefold in provides a counterexample to a recent conjecture of Cox and Katz concerning nef cones of toric hypersurfaces.
Received: 8 February 2001; in final form: 17 September 2001 / Published online: 1 February 2002 相似文献
23.
Graham Smith 《The Journal of the Operational Research Society》1989,40(9):761-770
Courses which teach discrete-event simulation are based on many different simulation languages. The requirements for a language to support teaching simulation are discussed. In particular, it is recommended that such languages separate into distinct modules those aspects of simulation which are taught as separate topics. Implementation of the separation is discussed. The SEESIM language, developed as a teaching aid, is described, and examples of its use are given. Straightforward use of SEESIM can be learned quickly, yet the language provides facilities for a staged introduction to advanced concepts of simulation. 相似文献
24.
A pressure sensitive paint (PSP) measurement has been known as a pressure field measurement technique based on the oxygen quenching phenomenon of luminescence of specific luminophores. A PSP measurement was applied for pressure field measurement in a low-solidity circular cascade diffuser of a single-stage transonic centrifugal compressor with 5 in pressure ratio for HFC134a gas. The oxygen concentration was about 500 ppm. Ru (bath-phen) was adsorbed on a silica-gel thinlayer chromatography sheet, and the sheet was pasted onto the side-wall between the cascade vanes. A drastic change in luminescent intensity was recognized during a surge condition. Also the pressure variations based on luminescent intensity agreed well with the pressure fluctuations measured using a semiconductor pressure sensor with high-frequency-response. It was shown that a PSP measurement worked well to investigate the unsteady pressure fields in a circular cascade diffuser of a transonic centrifugal compressor. Moreover, the time response of PSP becomes clear as a problem to be overcome for the present. 相似文献
25.
N. S. Simonović 《Few-Body Systems》2006,38(2-4):139-145
In agreement with the Kohn theorem the relative motion (rel) of three electrons in a two-dimensional parabolic trap separates
from the centre-of-mass (CM) motion. By introducing new coordinates the Hamiltonian for relative motion in the approximation
of non-interacting electrons can be taken to the normal form. The eigenstates of the normalized Hamiltonian are products of
the Fock-Darwin states for normal modes. The energy levels for relative motion are obtained by diagonalizing the exact Hamiltonian
in the eigenbasis for the non-interacting case. In this basis the interaction matrix elements can be obtained in the analytical
form. Since the rank of the Hamiltonian matrix is significantly reduced, the calculations are faster and more accurate than
those for the full (CM + rel) motion. This advantage is especially important for the calculations of excited states and the
analysis of energy spectra. 相似文献
26.
27.
Yasuyuki Kawahigashi 《Communications in Mathematical Physics》2002,226(2):269-287
We study the recent construction of subfactors by Rehren which generalizes the Longo–Rehren subfactors. We prove that if
we apply this construction to a non-degenerately braided subfactor N⊂M and α±-induction, then the resulting subfactor is dual to the Longo–Rehren subfactor M⊗M
opp⊂R arising from the entire system of irreducible endomorphisms of M resulting from αplusmn;-induction. As a corollary, we solve a problem on existence of braiding raised by Rehren negatively. Furthermore, we generalize
our previous study with Longo and Müger on multi-interval subfactors arising from a completely rational conformal net of factors
on S
1 to a net of subfactors and show that the (generalized) Longo–Rehren subfactors and α-induction naturally appear in this context.
Received: 11 September 2001 / Accepted: 7 October 2001 相似文献
28.
Julio Castellanos 《Mathematische Zeitschrift》2002,239(4):777-802
We consider complete ideals supported on finite sequences of infinitely near points, in regular local rings with dimensions
greater than two. We study properties of factorizations in Lipman special *-simple complete ideals. We relate it to a type
of proximity, linear proximity, of the points, and give conditions in order to have unique factorization. Several examples
are presented.
Received: 2 February 2000 / in final form: 14 March 2001 / Published online: 18 January 2002 相似文献
29.
30.
Claudia-Elisabeth Wulz 《Czechoslovak Journal of Physics》2002,52(3):C155-C170
The principal physics goals of the Compact Muon Solenoid experiment under construction at the Large Hadron Collider at CERN in Geneva are reviewed. Procedures to search for the Standard Model Higgs boson, supersymmetric Higgses and other supersymmetric particles are described. 相似文献