全文获取类型
收费全文 | 298277篇 |
免费 | 1538篇 |
国内免费 | 330篇 |
专业分类
化学 | 137171篇 |
晶体学 | 4651篇 |
力学 | 16876篇 |
综合类 | 3篇 |
数学 | 42034篇 |
物理学 | 99410篇 |
出版年
2021年 | 3104篇 |
2020年 | 3423篇 |
2019年 | 4197篇 |
2018年 | 6243篇 |
2017年 | 6450篇 |
2016年 | 7959篇 |
2015年 | 3532篇 |
2014年 | 6884篇 |
2013年 | 12128篇 |
2012年 | 10140篇 |
2011年 | 11804篇 |
2010年 | 9996篇 |
2009年 | 10140篇 |
2008年 | 11422篇 |
2007年 | 11218篇 |
2006年 | 9986篇 |
2005年 | 8614篇 |
2004年 | 8363篇 |
2003年 | 7778篇 |
2002年 | 8054篇 |
2001年 | 7671篇 |
2000年 | 6058篇 |
1999年 | 4488篇 |
1998年 | 4264篇 |
1997年 | 4128篇 |
1996年 | 3736篇 |
1995年 | 3296篇 |
1994年 | 3360篇 |
1993年 | 3375篇 |
1992年 | 3384篇 |
1991年 | 3790篇 |
1990年 | 3788篇 |
1989年 | 3795篇 |
1988年 | 3545篇 |
1987年 | 3630篇 |
1986年 | 3320篇 |
1985年 | 3850篇 |
1984年 | 4083篇 |
1983年 | 3488篇 |
1982年 | 3686篇 |
1981年 | 3372篇 |
1980年 | 3132篇 |
1979年 | 3621篇 |
1978年 | 3686篇 |
1977年 | 3855篇 |
1976年 | 3929篇 |
1975年 | 3671篇 |
1974年 | 3527篇 |
1973年 | 3691篇 |
1972年 | 3179篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
851.
A Stability Estimate for a Solution to a Three-Dimensional Inverse Problem for the Maxwell Equations
We consider the problem of determining dielectric permittivity and conductivity in the Maxwell equations. As additional information we prescribe the traces of the tangential components of the electromagnetic field on the lateral surface of a cylindric domain. We establish a stability estimate for a solution to the inverse problem and a uniqueness theorem. 相似文献
852.
V. V. Struzhanov V. V. Bashurov 《Journal of Applied Mechanics and Technical Physics》2003,44(4):549-556
Some iterative methods for calculating self-balanced stresses under shrinkage of a ball inclusion enclosed in a spherical matrix of a physically nonlinear damageable material. The stability of this system was studied using methods of catastrophe theory. It has been established that the beginning of divergence of the proposed iterative processes coincides with the moment of transition of the system to an unstable position of equilibrium. 相似文献
853.
The Sobolev functional class on a finite disjoint union of segments is described in terms of the rate of polynomial approximation. Bibliography: 9 titles. 相似文献
854.
855.
Russian Journal of General Chemistry - 相似文献
856.
In the present paper, the notion of norm series with respect to the norm residue symbol is generalized to high-dimensional local fields. Necessary and sufficient conditions for the existence of norm series are obtained. Bibliography: 12 titles.__________Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 305, 2003, pp. 60–83. 相似文献
857.
In this paper, we study the linearization of the Cauchy problem and the mixed problem for the system of Grad--Hermite moments in nonequilibrium thermodynamics in the neighborhood of the equilibrium state. Stability conditions for solutions of the Cauchy problem are proved as a generalization of the classical Hermite--Biller theorem on stable polynomials. For the mixed problem, we prove an analog of the Vishik--Lyusternik theorem on small singular perturbations of general elliptic problems. The last observation allows us to introduce the Shapiro--Lopatinskii condition, which implies the well-posedness of the mixed problem. 相似文献
858.
Matter implies the existence of a large-scale connected cluster of a uniform nature. The appearance of such clusters as a function of hadron density is specified by percolation theory. We can therefore formulate the freeze-out of interacting hadronic matter in terms of the percolation of hadronic clusters. The resulting freeze-out condition as a function of temperature and baryo-chemical potential interpolates between resonance gas behavior at low baryon density and repulsive nucleonic matter at low temperature, and it agrees well with the data.Received: 10 September 2003, Published online: 7 November 2003 相似文献
859.
Starting with a partition of a rectangular box into subboxes, it is shown how to construct a natural tetrahedral (type-4) partition and associated trivariate C 1 quintic polynomial spline spaces with a variety of useful properties, including stable local bases and full approximation power. It is also shown how the spaces can be used to solve certain Hermite and Lagrange interpolation problems. 相似文献
860.
A.D. Bykov V.N. Saveliev C. Camy-Peyret A. Valentin 《Journal of Molecular Spectroscopy》2004,224(2):164-175
Forty-seven N2 broadened water vapor line-widths have been measured in the 1845-2140 cm−1 spectral range with a Fourier Transform spectrometer in the 258-330 K temperature range at a spectral resolution of 0.005 cm−1 for the lines with upper state rotational quantum number up to 16. The measured exponents of the temperature dependence of the width exhibit a large range of values from 1.60 to −0.86. Theoretical calculations were made using a semi-empirical technique based on the Anderson theory. The calculated broadening coefficients as well as the temperature exponents for the half-width agree satisfactory with measured values. 相似文献