全文获取类型
收费全文 | 12961篇 |
免费 | 1162篇 |
国内免费 | 1185篇 |
专业分类
化学 | 1392篇 |
晶体学 | 21篇 |
力学 | 726篇 |
综合类 | 207篇 |
数学 | 10933篇 |
物理学 | 2029篇 |
出版年
2024年 | 23篇 |
2023年 | 141篇 |
2022年 | 122篇 |
2021年 | 210篇 |
2020年 | 242篇 |
2019年 | 313篇 |
2018年 | 315篇 |
2017年 | 374篇 |
2016年 | 420篇 |
2015年 | 295篇 |
2014年 | 566篇 |
2013年 | 1002篇 |
2012年 | 582篇 |
2011年 | 624篇 |
2010年 | 599篇 |
2009年 | 774篇 |
2008年 | 836篇 |
2007年 | 872篇 |
2006年 | 799篇 |
2005年 | 733篇 |
2004年 | 624篇 |
2003年 | 545篇 |
2002年 | 566篇 |
2001年 | 498篇 |
2000年 | 445篇 |
1999年 | 451篇 |
1998年 | 360篇 |
1997年 | 335篇 |
1996年 | 266篇 |
1995年 | 199篇 |
1994年 | 161篇 |
1993年 | 118篇 |
1992年 | 116篇 |
1991年 | 98篇 |
1990年 | 73篇 |
1989年 | 59篇 |
1988年 | 53篇 |
1987年 | 52篇 |
1986年 | 49篇 |
1985年 | 64篇 |
1984年 | 62篇 |
1983年 | 25篇 |
1982年 | 48篇 |
1981年 | 27篇 |
1980年 | 37篇 |
1979年 | 35篇 |
1978年 | 24篇 |
1977年 | 22篇 |
1976年 | 16篇 |
1974年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
121.
章志飞 《浙江大学学报(理学版)》2003,30(6):609-611
利用Besov空间的热核刻画及压缩映射原理,研究半线性热方程ut-△u=u|u|a的初值问题,得到了当初值u0∈Lp0(Rn)且||u0||(B·)p-n (1/p0-1/p),∞(Rn)(p0=na/2,p>p0)充分小时,整体解的存在性及在一定条件下解的惟一性. 相似文献
122.
Gheorghe Munteanu 《Periodica Mathematica Hungarica》2007,55(1):97-112
In [Mu1] we underlined the motifs of holomorphic subspaces in a complex Finsler space: induced nonlinear connection, coupling
connections, and the induced tangent and normal connections. In the present paper we investigate the equations of Gauss, H-and A-Codazzi, and Ricci equations of a holomorphic subspace. We deduce the link between the holomorphic curvatures of the Chern-Finsler
connection and its induced tangent connection. Conditions for totally geodesic holomorphic subspaces are obtained.
Communicated by János Szenthe 相似文献
123.
Let P(z) be a polynomial of degree n with complex coefficients and consider the n–th order linear differential operator P(D). We show that the equation P(D)f = 0 has the Hyers–Ulam stability, if and only if the equation P(z) = 0 has no pure imaginary solution. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
124.
This paper proposes a method for estimation of a class of partially linear single-index models with randomly censored samples. The method provides a flexible way for modelling the association between a response and a set of predictor variables when the response variable is randomly censored. It presents a technique for “dimension reduction” in semiparametric censored regression models and generalizes the existing accelerated failure-time models for survival analysis. The estimation procedure involves three stages: first, transform the censored data into synthetic data or pseudo-responses unbiasedly; second, obtain quasi-likelihood estimates of the regression coefficients in both linear and single-index components by an iteratively algorithm; finally, estimate the unknown nonparametric regression function using techniques for univariate censored nonparametric regression. The estimators for the regression coefficients are shown to be jointly root-n consistent and asymptotically normal. In addition, the estimator for the unknown regression function is a local linear kernel regression estimator and can be estimated with the same efficiency as all the parameters are known. Monte Carlo simulations are conducted to illustrate the proposed methodology. 相似文献
125.
Veli B. Shakhmurov 《Journal of Mathematical Analysis and Applications》2007,327(2):1182-1201
The nonlocal boundary value problems for anisotropic partial differential-operator equations with a dependent coefficients are studied. The principal parts of the appropriate generated differential operators are nonself-adjoint. Several conditions for the maximal regularity and the fredholmness in Banach-valued Lp-spaces of these problems are given. These results permit us to establish that the inverse of corresponding differential operators belongs to Schatten q-class. Some spectral properties of the operators are investigated. In applications, the nonlocal BVP's for quasielliptic partial differential equations and for systems of quasielliptic equations on cylindrical domain are studied. 相似文献
126.
Florence Newberger 《Geometriae Dedicata》2003,97(1):215-249
The goal of this paper is to provide a tool, the Global Measure Formula, that will facilitate the study of the limit set of discrete geometrically finite groups of isometries of the rank one symmetric spaces. We consider the shadow of a ball from a fixed reference point onto the boundary, and prove a formula that describes the measure of the shadow in terms of the center of the shadowed ball, generalizing a result from real hyperbolic geometry. 相似文献
127.
In this paper, we provide bounds for the expected value of the log of the condition number C(A) of a linear feasibility problem given by a n × m matrix A (Ref. 1). We show that this expected value is O(min{n, m log n}) if n > m and is O(log n) otherwise. A similar bound applies for the log of the condition number C
R(A) introduced by Renegar (Ref. 2). 相似文献
128.
129.
The many facets of linear programming 总被引:1,自引:0,他引:1
Michael J. Todd 《Mathematical Programming》2002,91(3):417-436
We examine the history of linear programming from computational, geometric, and complexity points of view, looking at simplex,
ellipsoid, interior-point, and other methods.
Received: June 22, 2000 / Accepted: April 4, 2001?Published online October 2, 2001 相似文献
130.
1IntroductionConsiderthelinearregressioumodelcensoredfromtheleft:K=m{K,0}=rnax{Z:W ei,0},1Si5n,(1.1)whereZi=(1,X:),,15i5n,7o=(ac,P6)'(1'2)ThedimensionalityofXiisd21.WeobBerve(Xi,K)',1SiSn.Basedontheseobservations,wetrytogivesomeestimationofac,ortesthypothesisonit.Themodelwasfirstconsideredbycabin[llundertheassumptionthatelfe2,''arelid.withacommonnormaldistributionN(0,rs:).HedefinedtheMLEof7o,whichnowisusuallyknownastheTobinestimator.TheconsistencyOfthisestimatorwasestablishedbyAmend… 相似文献