首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3041篇
  免费   198篇
  国内免费   293篇
化学   196篇
晶体学   3篇
力学   133篇
综合类   51篇
数学   2497篇
物理学   652篇
  2024年   4篇
  2023年   28篇
  2022年   41篇
  2021年   49篇
  2020年   66篇
  2019年   67篇
  2018年   77篇
  2017年   78篇
  2016年   100篇
  2015年   63篇
  2014年   149篇
  2013年   243篇
  2012年   125篇
  2011年   177篇
  2010年   159篇
  2009年   161篇
  2008年   237篇
  2007年   201篇
  2006年   190篇
  2005年   164篇
  2004年   142篇
  2003年   141篇
  2002年   146篇
  2001年   105篇
  2000年   92篇
  1999年   94篇
  1998年   99篇
  1997年   63篇
  1996年   54篇
  1995年   38篇
  1994年   29篇
  1993年   20篇
  1992年   15篇
  1991年   6篇
  1990年   19篇
  1989年   12篇
  1988年   8篇
  1987年   4篇
  1986年   10篇
  1985年   10篇
  1984年   9篇
  1982年   6篇
  1981年   6篇
  1980年   4篇
  1979年   4篇
  1978年   4篇
  1977年   2篇
  1976年   3篇
  1973年   3篇
  1936年   2篇
排序方式: 共有3532条查询结果,搜索用时 15 毫秒
991.
Let(X,p,μ)d,θ be a space of homogeneous type,(?) ∈(0,θ],|s|<(?) andmax{d/(d+(?)),d/(d+s+(?))}<q≤∞.The author introduces the new Triebel-Lizorkin spaces (?)_∞q~s(X) and establishes the framecharacterizations of these spaces by first establishing a Plancherel-P(?)lya-type inequalityrelated to the norm of the spaces (?)_∞q~s(X).The frame characterizations of the Besovspace (?)_pq~s(X) with|s|<(?),max{d/(d+(?)),d/(d+s+(?))}<p≤∞ and 0<q≤∞and the Triebel-Lizorkin space (?)_pq~s(X)with|s|<(?),max{d/(d+(?)),d/(d+s+(?))}<p<∞ and max{d/(d+(?)),d/(d+s+(?))}<q≤∞ are also presented.Moreover,the au-thor introduces the new TriebeI-Lizorkin spaces b(?)_∞q~s(X) and H(?)_∞q~s(X) associated to agiven para-accretive function b.The relation between the space b(?)_∞q~s(X) and the spaceH(?)_∞q~s(X) is also presented.The author further proves that if s=0 and q=2,thenH(?)_∞q~s(X)=(?)_∞q~s(X),which also gives a new characterization of the space BMO(X),since (?)_∞q~s(X)=BMO(X).  相似文献   
992.
基于范德瓦尔斯气体的迈耶公式修正   总被引:1,自引:0,他引:1  
在近似真实情况下,对迈耶公式作了理论修正,并与实验值进行了比较.  相似文献   
993.
各向同性谐振子是量子理论中能够严格求解的可解势场之一.对它的研究和讨论,在理论上和实际的应用中都有重要意义.本文推导出了N维(N≥2)各向同性谐振子径向矩阵元〈nrl|rk|nr′l′〉的递推公式,在此基础上得到了平均值的递推公式,并且讨论了维各向同性谐振子径向矩阵元的递推公式的一般性,而文献[3]与[4]所给出的各向同性谐振子径向矩阵元的递推公式只是本文结论的特例.  相似文献   
994.
This paper belongs to a broad line of research leaded by Herrera, which encompasses a good number of numerical methods such as Localized Adjoint Method (LAM), Eulerian-Lagrangian LAM (ELAM) and Trefftz-Herrera Method. The results presented in this paper are required in order to incorporate Herrera's general theory in a Sobolev-space setting. In particular, this article introduces a class of partitions (or domain decompositions) whose internal boundaries belong to a category of manifolds with corners, here also presented. Then a version of Gauss (or divergence) theorem, in a wider sense, is established and an explicit integral formula is associated for any given linear partial differential operator L, its adjoint and concomitant. The structure of the bilinear concomitant induced by L is first determined. Then the required formula is given over that class of domain decompositions. Finally, an integral formula well on the way of the Green-Herrera formula is settled.  相似文献   
995.
Wan Keng Cheong 《代数通讯》2013,41(12):4575-4587
We prove a closed formula for an excess integral over the moduli space of stable maps from genus one, unmarked curves to the projective space ? r of degree d for any positive integers r and d. The result generalizes the multiple cover formula for ?1. We also show that any simple ? r flop preserves the theory of arbitrary-genus Gromov-Witten invariants in exceptional curve classes.  相似文献   
996.
Using the T1 theorem for the Besov and Triebel-Lizorkin spaces, we give new characterizations of Besov and Triebel-Lizorkin spaces with minimum regularity and cancellation conditions over spaces of homogeneous type.  相似文献   
997.
Numerical Solution for the Helmholtz Equation with Mixed Boundary Condition   总被引:1,自引:0,他引:1  
We consider the numerical solution for the Helmholtz equation in R~2 with mixed boundary conditions.The solvability of this mixed boundary value problem is estab- lished by the boundary integral equation method.Based on the Green formula,we express the solution in terms of the boundary data.The key to the numerical real- ization of this method is the computation of weakly singular integrals.Numerical performances show the validity and feasibility of our method.The numerical schemes proposed in this paper have been applied in the realization of probe method for inverse scattering problems.  相似文献   
998.
For any tree Γ, we introduce Γ-cones consisting of chambers and enumerate the number of chambers contained in two particular (called principal) Γ-cones. The problem is equivalent to the combinatorial problem of the enumeration of linear extensions of two bipartite orderings on a tree Γ. We characterize the principal Γ-cones among other Γ-cones by the strict maximality of the number of their chambers, and give a formula for this maximal (called principal) number by a finite sum of hook length formulae. We explain the formula through the simplicial block decomposition of principal Γ-cones. The results have their origin and application in the study of the topology related to Coxeter groups and Artin groups.  相似文献   
999.
In this paper we make some further extensions of discrete Hilbert's inequality by using Euler-Maclaurin summation formula. We give the improvements of some previously obtained results and also compare our results with some previously known from the literature.  相似文献   
1000.
Lv Longjin  Fu-Yao Ren  Wei-Yuan Qiu 《Physica A》2010,389(21):4809-1752
In this paper, in order to establish connection between fractional derivative and fractional Brownian motion (FBM), we first prove the validity of the fractional Taylor formula proposed by Guy Jumarie. Then, by using the properties of this Taylor formula, we derive a fractional Itô formula for H∈[1/2,1), which coincides in form with the one proposed by Duncan for some special cases, whose formula is based on the Wick Product. Lastly, we apply this fractional Itô formula to the option pricing problem when the underlying of the option contract is supposed to be driven by a geometric fractional Brownian motion. The case that the drift, volatility and risk-free interest rate are all dependent on t is also discussed.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号