全文获取类型
收费全文 | 77655篇 |
免费 | 321篇 |
国内免费 | 374篇 |
专业分类
化学 | 23929篇 |
晶体学 | 788篇 |
力学 | 6719篇 |
数学 | 31924篇 |
物理学 | 14990篇 |
出版年
2018年 | 10435篇 |
2017年 | 10259篇 |
2016年 | 6052篇 |
2015年 | 833篇 |
2014年 | 280篇 |
2013年 | 297篇 |
2012年 | 3755篇 |
2011年 | 10470篇 |
2010年 | 5612篇 |
2009年 | 6025篇 |
2008年 | 6568篇 |
2007年 | 8728篇 |
2006年 | 197篇 |
2005年 | 1281篇 |
2004年 | 1508篇 |
2003年 | 1953篇 |
2002年 | 998篇 |
2001年 | 239篇 |
2000年 | 284篇 |
1999年 | 149篇 |
1998年 | 188篇 |
1997年 | 142篇 |
1996年 | 194篇 |
1995年 | 114篇 |
1994年 | 74篇 |
1993年 | 92篇 |
1992年 | 52篇 |
1991年 | 62篇 |
1990年 | 49篇 |
1989年 | 58篇 |
1988年 | 58篇 |
1987年 | 58篇 |
1986年 | 57篇 |
1985年 | 46篇 |
1984年 | 42篇 |
1983年 | 36篇 |
1982年 | 41篇 |
1981年 | 38篇 |
1980年 | 46篇 |
1979年 | 44篇 |
1978年 | 34篇 |
1973年 | 25篇 |
1914年 | 45篇 |
1913年 | 40篇 |
1912年 | 40篇 |
1910年 | 24篇 |
1909年 | 41篇 |
1908年 | 40篇 |
1907年 | 32篇 |
1904年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
271.
On the characterisation of paired monotone metrics 总被引:1,自引:1,他引:0
Paolo Gibilisco Tommaso Isola 《Annals of the Institute of Statistical Mathematics》2004,56(2):369-381
Hasegawa and Petz introduced the notion of paired monotone metrics. They also gave a characterisation theorem showing that
Wigner-Yanase-Dyson metrics are the only members of the paired family. In this paper we show that the characterisation theorem
holds true under hypotheses that are more general than those used in the above quoted references. 相似文献
272.
273.
Let A be a Weil algebra. The bijection between all natural operators lifting vector fields from m-manifolds to the bundle functor K
A
of Weil contact elements and the subalgebra of fixed elements SA of the Weil algebra A is determined and the bijection between all natural affinors on K
A
and SA is deduced. Furthermore, the rigidity of the functor K
A
is proved. Requisite results about the structure of SA are obtained by a purely algebraic approach, namely the existence of nontrivial SA is discussed. 相似文献
274.
Richard P. Stanley 《Israel Journal of Mathematics》2004,143(1):317-339
We survey three recent developments in algebraic combinatorics. The first is the theory of cluster algebras and the Laurent
phenomenon of Sergey Fomin and Andrei Zelevinsky. The second is the construction of toric Schur functions and their application
to computing three-point Gromov-Witten invariants, by Alexander Postnikov. The third development is the construction of intersection
cohomology for nonrational fans by Paul Bressler and Valery Lunts and its application by Kalle Karu to the torich-vector of a nonrational polytope. We also briefly discuss the “half hard Lefschetz theorem” of Ed Swartz and its application
to matroid complexes.
Partially supported by NSF grant #DMS-9988459. 相似文献
275.
Mieko Tanaka-Yamawaki 《Annals of the Institute of Statistical Mathematics》2003,55(2):437-446
Contrary to the common sense in economics and financial engineering, price fluctuations at very fine level of motion exhibit
various evidences against the efficient market hypothesis. We attempt to investigate this issue by studying extensive amount
of foreign currency exchange data for over five years at the finest level of resolution. We specifically focus on the proposed
stability in binomial conditional probabilities originally found in much smaller examples of financial time series. In order
to handle very large data, we have written an efficient program in C that automatically generates those conditional probabilities.
It is found that the stability is maintained for extremely large time duration that covers almost the entire period. Based
on the length of conditions for which the conditional probabilities are distinguishable each other, we identify the length
of memory being less than 3 movements. 相似文献
276.
All homothetic self-similar solutions of the Brans-Dicke scalar field in three-dimensional spacetime with circular symmetry
are found in closed form. 相似文献
277.
Fabio Scardigli 《Foundations of Physics》2007,37(8):1278-1295
The Titius–Bode law for planetary distances is reviewed. A model describing the basic features of this rule in the “quantum-like”
language of a wave equation is proposed. Some considerations about the ’t Hooft idea on the quantum behavior of deterministic
systems with dissipation are discussed. 相似文献
278.
We study the metrical theory of fibred systems, in particular, in the case of continued fraction mixing systems. We get the
limit distribution of the largest value of a continued fraction mixing stationary stochastic process with infinite expectation
and some related results. These are analogous to J. Galambos, W. Philipp, and H. G. Diamond–J. D. Vaaler theorems for the
regular continued fractions. As an application, we see that these theorems hold for Jacobi-Perron algorithm.
Received September 30, 2001; in revised form January 8, 2002 相似文献
279.
The shock structure problem is one of the classical problems of fluid mechanics and at least for non-reacting dilute gases it has been considered essentially solved. Here we present a few recent findings, to show that this is not the case. There are still new physical effects to be discovered provided that the numerical technique is general enough to not rule them out a priori. While the results have been obtained for dense fluids, some of the effects might also be observable for shocks in dilute gases. 相似文献
280.
It is shown that time-dependent temperatures in a transient, conductive system can be approximately modeled by a fractional-order
differential equation, the order of which depends on the Biot number. This approximation is particularly suitable for complex
shapes for which a first-principles approach is too difficult or computationally time-consuming. Analytical solutions of these
equations can be written in terms of the Mittag-Leffler function. The approximation is especially useful if a suitable fractional-order
controller is to be designed for the system. 相似文献