全文获取类型
收费全文 | 5449篇 |
免费 | 726篇 |
国内免费 | 971篇 |
专业分类
化学 | 2355篇 |
晶体学 | 40篇 |
力学 | 347篇 |
综合类 | 75篇 |
数学 | 3339篇 |
物理学 | 990篇 |
出版年
2024年 | 14篇 |
2023年 | 116篇 |
2022年 | 131篇 |
2021年 | 189篇 |
2020年 | 305篇 |
2019年 | 290篇 |
2018年 | 237篇 |
2017年 | 338篇 |
2016年 | 285篇 |
2015年 | 202篇 |
2014年 | 352篇 |
2013年 | 473篇 |
2012年 | 399篇 |
2011年 | 334篇 |
2010年 | 236篇 |
2009年 | 315篇 |
2008年 | 324篇 |
2007年 | 313篇 |
2006年 | 274篇 |
2005年 | 255篇 |
2004年 | 279篇 |
2003年 | 217篇 |
2002年 | 179篇 |
2001年 | 125篇 |
2000年 | 130篇 |
1999年 | 130篇 |
1998年 | 84篇 |
1997年 | 99篇 |
1996年 | 98篇 |
1995年 | 74篇 |
1994年 | 54篇 |
1993年 | 46篇 |
1992年 | 46篇 |
1991年 | 35篇 |
1990年 | 26篇 |
1989年 | 19篇 |
1988年 | 15篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 13篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 11篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1959年 | 3篇 |
1936年 | 5篇 |
排序方式: 共有7146条查询结果,搜索用时 250 毫秒
71.
We establish the similarity between certain Volterra integral operators and the Riemann--Liouville fractional integration operator as well as the existence of a triangular transformation operator for integro-differential equations of fractional order. The results obtained are consistent with similar results for the case of integer order. 相似文献
72.
THE SCHWARZIAN DERIVATIVE IN SEVERAL COMPLEX VARIABLES(II) 总被引:1,自引:0,他引:1
THESCHWARZIANDERIVATIVEINSEVERALCOMPLEXVARIABLES(II)GONGSHENGYUQIHUANGZHENGXUEANManuscriptreceivedAugust30,1996.De... 相似文献
73.
CONE-DIRECTED CONTINGENT DERIVATIVES AND GENERALIZED PREINVEX SET-VALUED OPTIMIZATION 总被引:2,自引:0,他引:2
丘京辉 《数学物理学报(B辑英文版)》2007,27(1):211-218
By using cone-directed contingent derivatives, the unified necessary and suffi-cient optimality conditions are given for weakly and strongly minimal elements respectively in generalized preinvex set valued optimization. 相似文献
74.
Dong Sheng WU Yi Min XIAO 《数学学报(英文版)》2007,23(4):613-622
Let B^α = {B^α(t),t E R^N} be an (N,d)-fractional Brownian motion with Hurst index α∈ (0, 1). By applying the strong local nondeterminism of B^α, we prove certain forms of uniform Hausdorff dimension results for the images of B^α when N 〉 αd. Our results extend those of Kaufman for one-dimensional Brownian motion. 相似文献
75.
L. G. Mezhlumyan Sh. Kh. Rakhimova P. Kh. Yuldashev N. K. Aikhodzhaeva M. A. Saidkhodzhaeva A. I. Massino S. Makhmudova 《Chemistry of Natural Compounds》2004,40(1):59-62
The glutelin fraction was used as the food value index of local corn. The base-soluble fraction was used as a test of the glassiness of local strains of rice grain. The content of gliadins and glutelins did not change over 24 h after wheat grain cultivated in Uzbekistan was moistened. 相似文献
76.
This article explores the use of geometric algebra in linear and multilinear algebra, and in affine, projective and conformal geometries. Our principal objective is to show how the rich algebraic tools of geometric algebra are fully compatible with and augment the more traditional tools of matrix algebra. The novel concept of an h-twistor makes possible a simple new proof of the striking relationship between conformal transformations in a pseudo-Euclidean space to isometries in a pseudo-Euclidean space of two higher dimensions. The utility of the h-twistor concept, which is a generalization of the idea of a Penrose twistor to a pseudo-Euclidean space of arbitrary signature, is amply demonstrated in a new treatment of the Schwarzian derivative. 相似文献
77.
In the present paper, we solve three boundary value problems related to the temperature field in oil strata — the fractional
extensions of the incomplete lumped formulation and lumped formulation in the linear case and the fractional generalization
of the incomplete lumped formulation in the radial case. By using the Caputo differintegral operator and the Laplace transform,
the solutions are obtained in integral forms where the integrand is expressed in terms of the convolution of some auxiliary
functions of Wright function type. A generalization of the Laplace transform convolution theorem, known as Efros’ theorem
is widely used. 相似文献
78.
Our purpose is to characterize the multiparameter Gaussian processes, that is Gaussian sheets, that are equivalent in law
to the Brownian sheet and to the fractional Brownian sheet. We survey multiparameter analogues of the Hitsuda, Girsanov and
Shepp representations. As an application, we study a special type of stochastic equation with linear noise.
相似文献
79.
Hidefumi Kawasaki 《Mathematical Programming》1988,41(1-3):327-339
The purpose of this paper is to give a formula for expressing the second order directional derivatives of the sup-type functionS(x) = sup{f(x, t); t T} in terms of the first and second derivatives off(x, t), whereT is a compact set in a metric space and we assume thatf, f/x and
2
f/x
2 are continuous on
n
× T. We will give a geometrical meaning of the formula. We will moreover give a sufficient condition forS(x) to be directionally twice differentiable. 相似文献
80.
比光谱-导数吸光光度法及其应用与进展 总被引:1,自引:1,他引:1
综述了比光谱-导数吸光光度法的基本原理、主要试验条件的选择及其在多组分混合物同时测定中的应用与进展。全文共引用了参考文献50篇。 相似文献