全文获取类型
收费全文 | 679篇 |
免费 | 10篇 |
国内免费 | 9篇 |
专业分类
化学 | 211篇 |
晶体学 | 2篇 |
力学 | 16篇 |
数学 | 298篇 |
物理学 | 171篇 |
出版年
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 10篇 |
2016年 | 15篇 |
2015年 | 5篇 |
2014年 | 11篇 |
2013年 | 33篇 |
2012年 | 26篇 |
2011年 | 27篇 |
2010年 | 14篇 |
2009年 | 13篇 |
2008年 | 24篇 |
2007年 | 32篇 |
2006年 | 38篇 |
2005年 | 36篇 |
2004年 | 24篇 |
2003年 | 21篇 |
2002年 | 21篇 |
2001年 | 8篇 |
2000年 | 13篇 |
1999年 | 10篇 |
1998年 | 7篇 |
1997年 | 8篇 |
1996年 | 15篇 |
1995年 | 11篇 |
1994年 | 15篇 |
1993年 | 14篇 |
1992年 | 20篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 16篇 |
1984年 | 17篇 |
1983年 | 12篇 |
1982年 | 15篇 |
1981年 | 14篇 |
1980年 | 9篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1975年 | 12篇 |
1974年 | 9篇 |
1973年 | 3篇 |
1971年 | 2篇 |
1967年 | 3篇 |
排序方式: 共有698条查询结果,搜索用时 78 毫秒
171.
Moshe Gitterman 《Journal of statistical physics》1992,69(5-6):1153-1153
172.
We prove a generalization to the totally real field case of the Waldspurger’s formula relating the Fourier coefficient of
a half integral weight form and the central value of the L-function of an integral weight form. Our proof is based on a new interpretation of Waldspurger’s formula as a combination
of two ingredients – an equality between global distributions, and a dichotomy result for theta correspondence. As applications
we generalize the Kohnen–Zagier formula for holomorphic forms and prove the equivalence of the Ramanujan conjecture for half
integral weight forms and a case of the Lindel?f hypothesis for integral weight forms. We also study the Kohnen space in the
adelic setting.
The first author was partially supported by NSF grant DMS-0070762. The second author was partially supported by NSF grant
DMS-0355285.
Received: July 2005 Accepted: August 2005 相似文献
173.
Moshe Sniedovich Emmanuel Macalalag Suzanne Findlay 《Journal of Global Optimization》1994,4(1):89-109
In this paper we give a brief account of the important role that the conventional simplex method of linear programming can play in global optimization, focusing on its collaboration with composite concave programming techniques. In particular, we demonstrate how rich and powerful the c-programming format is in cases where its parametric problem is a standard linear programming problem. 相似文献
174.
Consider a diffusion process on an infinite line terminated by a trap and modulated by a periodic field. When the frequency is equal to zero the mean time to trapping will be finite or infinite, depending on the sign of the field. We ask whether this behavior can be changed by an oscillatory field, and show that it cannot for pure Brownian motion. We suggest that transition can appear when the signal propagation velocity is finite as for the telegrapher's equation. We further suggest that the asymptotic time dependence of the survival probability is proportional tot
–1/2 just as in the case of ordinary diffusion. The same conclusion is shown to hold for a system whose dynamics is governed by the equation
, whereL is a constant. 相似文献
175.
We introduce a new service discipline, called thesynchronized gated discipline, for polling systems. It arises when there are precedence (or synchronization) constraints between the order that jobs in different qucues should be served. These constraints are described as follows: There areN stations which are fathers of (zero or more)synchronized stations (children). Jobs that arrive at synchronized stations have to be processed only after jobs that arrived prior to them at their corresponding father station have been processed. We analyze the performance of the synchronized gated discipline and obtain expressions for the first two moments and the Laplace-Stieltjes transform (LST) of the waiting times in different stations, and expressions for the moments and LST of other quantities of interest, such as cycle duration and generalized station times. We also obtain a pscudo conservation law for the synchronized gated discipline, and determine the optimal network topology that minimizes the weighted sum of the mean waiting times, as defined in the pseudo conservation law. Numerical examples are given for illustrating the dependence of the performance of the synchronized gated discipline on different parameters of the network.Supported by a Grant from the France-Israel Scientific Cooperation (in Computer Science and Engineering) between the French Ministry of Research and Technology and the Israeli Ministry of Science and Technology, Grant No. 3321190. 相似文献
176.
Summary LetT()=+F() be a transformation from the Wiener space to itself with the range ofF() assumed to be in the Cameron-Martin space. The absolute continuity and the density function associated withT is considered;T is assumed to be embedded in or defined through a parameterizationT
t
=+F
t
() andF
t
is assumed to be differentiable int. The paper deals first with the case where the range of thet-derivative ofF
t
() is also in the Cameron-Martin space and new representations for the Radon-Nikodym derivative and the Carleman-Fredholm determinant are derived. The case where thet-derivative ofF
t
is not in the Cameron-Martin space is considered next and results on the absolute continuity and the density function, under conditions which are considerably weaker than previously known conditions, are presented.The work of the second author was supported by the fund for promotion of research at the Technion 相似文献
177.
178.
Natural bounded concentrators 总被引:1,自引:0,他引:1
Moshe Morgenstern 《Combinatorica》1995,15(1):111-122
We give the first known direct construction for linear families of bounded concentrators. The construction is explicit and
the results are simple natural bounded concentrators.
Let
be the field withq elements,g(x)∈F
q
[x] of degree greater than or equal to 2,
and
. LetI
nputs=H/A,O
utputs=H/B, and draw an edge betweenaA andbB iffaA∩bB≠ϕ. We prove that for everyq≥5 this graph is an
concentrator.
Part of this research was done while the author was at the department of Computer Science, The University of British Columbia,
Vancouver, B.C., Canada. 相似文献
179.
We present a summary of recent NP-hardness and polynomial time solvability results for the distinction between strong and weak precedence for chains and trees in scheduling. We distinguish between chains and proper trees which are not chains, and demonstrate that the strong-weak precedence distinction for chains is not inclusive with regards to NP-hardness, and conjecture that the same holds for strong-weak tree precedence. The objective is to show that different interpretations for chain and tree order relations in scheduling might have far reaching computational implications. 相似文献
180.
Dispersion polymerization of styrene in the particle size range of 10 μ with lauroyl peroxide as initiator results in a double-peak molecular weight (MW) distribution. The high-MW fraction was due to emulsion polymerization. The same phenomenon also exists in AIBN and benzoyl peroxide initiation, although it is less obvious. The kinetics of the reaction for dispersion polymerization was dependent on the concentration of the dispersing agent and the nature of the initiator. 相似文献