全文获取类型
收费全文 | 180947篇 |
免费 | 796篇 |
国内免费 | 267篇 |
专业分类
化学 | 90593篇 |
晶体学 | 2646篇 |
力学 | 9393篇 |
综合类 | 7篇 |
数学 | 20965篇 |
物理学 | 58406篇 |
出版年
2020年 | 1859篇 |
2019年 | 2309篇 |
2018年 | 3401篇 |
2017年 | 3534篇 |
2016年 | 4170篇 |
2015年 | 1864篇 |
2014年 | 3608篇 |
2013年 | 7133篇 |
2012年 | 5571篇 |
2011年 | 6637篇 |
2010年 | 5536篇 |
2009年 | 5674篇 |
2008年 | 6424篇 |
2007年 | 6378篇 |
2006年 | 5668篇 |
2005年 | 5026篇 |
2004年 | 4866篇 |
2003年 | 4425篇 |
2002年 | 4564篇 |
2001年 | 5030篇 |
2000年 | 3732篇 |
1999年 | 2846篇 |
1998年 | 2617篇 |
1997年 | 2476篇 |
1996年 | 2267篇 |
1995年 | 2057篇 |
1994年 | 2025篇 |
1993年 | 2053篇 |
1992年 | 2106篇 |
1991年 | 2399篇 |
1990年 | 2331篇 |
1989年 | 2403篇 |
1988年 | 2288篇 |
1987年 | 2319篇 |
1986年 | 2143篇 |
1985年 | 2681篇 |
1984年 | 2689篇 |
1983年 | 2329篇 |
1982年 | 2382篇 |
1981年 | 2293篇 |
1980年 | 2089篇 |
1979年 | 2418篇 |
1978年 | 2565篇 |
1977年 | 2651篇 |
1976年 | 2740篇 |
1975年 | 2548篇 |
1974年 | 2480篇 |
1973年 | 2654篇 |
1972年 | 2155篇 |
1971年 | 1975篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
The rotational spectra of 34SO2F2 and S18O16OF2 have been measured in their ground vibrational state between 9 and 110 GHz. Accurate rotational constants have been derived. Various experimental structures including the average structure have been determined. The ab initio structure has been calculated at the CCSD(T) level of theory. The different structures are compared and the best equilibrium structure is the ab initio structure: re(SO)=1.401 (3) Å, re(SF)=1.532 (3) Å, ∠e(OSO)=124.91(20)°, ∠e(FSF)=95.53 (20)°. 相似文献
123.
The method of nonlinear moments, when used to solve the Boltzmann equation, necessitates the calculation of collision integral
matrix elements. The matrix elements are hard to calculate numerically, especially at large indices. The asymptotics of the
matrix elements are constructed. In terms of the model of pseudopower particle interaction, a formula free of summation is
derived. This makes it possible to find the asymptotic behavior of linear and nonlinear elements when two indices are large.
For an arbitrary interaction cross section, asymptotic expansions of linear and nonlinear matrix elements in one index are
obtained. For Maxwellian molecules, asymptotic formulas are derived for three large indices. 相似文献
124.
The fine-structure parameters of a series of configurations of the first ion of indium and the gyromagnetic ratios in intermediate coupling are calculated by a semiempirical method in the single-configuration approximation. 相似文献
125.
126.
We obtain exponential upper bounds for tails of distributions of generalized L-statistics based on a sample from an exponential distribution. We prove the asymptotic normality of generalized L-statistics based on a sample from the uniform distribution on [0,1] and of L-statistics with decomposed kernels (without any restrictions on the sample distribution type). 相似文献
127.
128.
Lobanovsky L. S. Troyanchuk I. O. 《Journal of Experimental and Theoretical Physics》2003,96(2):331-334
Journal of Experimental and Theoretical Physics - The magnetoresistance effect in the SmCu3Mn4O12 compound with a perovskite-like structure is investigated for the first time. It is found that an... 相似文献
129.
We examine several interesting relationships and expressions involving Fourier-Feynman transform, convolution product and
first variation for functionals in the Fresnel class F(B) of an abstract Wiener space B. We also prove a translation theorem and Parseval's identity for the analytic Feynman integral.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
130.
In basin modelling the thermodynamics of a multicomponent multiphase fluid flux are computationally too expensive when derived from an equation of state and the Gibbs equality constraints. In this article we present a novel implicit molar mass formulation technique using binary mixture thermodynamics. The two proposed solution methods, with and without cross derivative terms between components, are based on a preconditioned Newton‐GMRES scheme for each time‐step with analytical computation of the derivatives. These new algorithms reduce significantly the numerical effort for the computation of the molar masses, and we illustrate the behavior of these methods with numerical computations. Copyright © 2004 John Wiley & Sons Ltd. 相似文献