全文获取类型
收费全文 | 2995篇 |
免费 | 198篇 |
国内免费 | 291篇 |
专业分类
化学 | 193篇 |
晶体学 | 3篇 |
力学 | 127篇 |
综合类 | 51篇 |
数学 | 2495篇 |
物理学 | 615篇 |
出版年
2024年 | 3篇 |
2023年 | 24篇 |
2022年 | 36篇 |
2021年 | 47篇 |
2020年 | 64篇 |
2019年 | 66篇 |
2018年 | 76篇 |
2017年 | 77篇 |
2016年 | 98篇 |
2015年 | 60篇 |
2014年 | 149篇 |
2013年 | 237篇 |
2012年 | 122篇 |
2011年 | 176篇 |
2010年 | 158篇 |
2009年 | 158篇 |
2008年 | 236篇 |
2007年 | 201篇 |
2006年 | 190篇 |
2005年 | 162篇 |
2004年 | 140篇 |
2003年 | 140篇 |
2002年 | 144篇 |
2001年 | 104篇 |
2000年 | 92篇 |
1999年 | 94篇 |
1998年 | 99篇 |
1997年 | 63篇 |
1996年 | 54篇 |
1995年 | 37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 | 3篇 |
1986年 | 9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3484条查询结果,搜索用时 46 毫秒
101.
我们用三角和的性质研究一类三次Gauss和与两项指数和混合均值的计算问题,并给出一个精确的计算公式. 相似文献
102.
We revisit the derivation of the microscopic stress, linking the statistical mechanics of particle systems and continuum mechanics. The starting point in our geometric derivation is the Doyle–Ericksen formula, which states that the Cauchy stress tensor is the derivative of the free-energy with respect to the ambient metric tensor and which follows from a covariance argument. Thus, our approach to define the microscopic stress tensor does not rely on the statement of balance of linear momentum as in the classical Irving–Kirkwood–Noll approach. Nevertheless, the resulting stress tensor satisfies balance of linear and angular momentum. Furthermore, our approach removes the ambiguity in the definition of the microscopic stress in the presence of multibody interactions by naturally suggesting a canonical and physically motivated force decomposition into pairwise terms, a key ingredient in this theory. As a result, our approach provides objective expressions to compute a microscopic stress for a system in equilibrium and for force-fields expanded into multibody interactions of arbitrarily high order. We illustrate the proposed methodology with molecular dynamics simulations of a fibrous protein using a force-field involving up to 5-body interactions. 相似文献
103.
104.
105.
106.
《复变函数与椭圆型方程》2012,57(15):1163-1164
Let X be a smooth and connected Riemann surface of genus g 0 and f: X P1, h: X P1 non-constant meromorphic functions on X. Fix an integer n 4 and assume the existence of n distinct points a1, , an P1 such that [image omitted] (set-theoretically) for every i. Here we prove that either f = h or [image omitted]. 相似文献
107.
Scattering neutrons are one of the key factors that may affect the images of fast neutron radiog- raphy. In this paper, a mathematical model for scattered neutrons is developed on a cylinder sample, and an empirical formula for scattered neutrons is obtained. According to the results given by Monte Carlo methods, the parameters in the empirical formula are obtained with curve fitting, which confirms the logicality of the empirical formula. The curve-fitted parameters of common materials such as <'6>LiD are given. 相似文献
108.
《Optimization》2012,61(8):1009-1028
Bilevel convex models are studied after being cast into a parametric programming form. This form has a lexicographic inner-outer structure where the optimal value of the outer model is optimized on the set of optimal solutions of the inner model. Optimal solutions are characterized using a Lagrangian saddle-point approach and a marginal value formula is given for the outer model. These are used to formulate a general method for finding an optimal solution by input optimization. 相似文献
109.
110.
In this Letter, a generalized Tu formula is firstly presented to construct Hamiltonian structures of fractional soliton equations. The obtained results can be reduced to the classical Hamiltonian hierarchy of AKNS in ordinary calculus. 相似文献