全文获取类型
收费全文 | 5952篇 |
免费 | 555篇 |
国内免费 | 563篇 |
专业分类
化学 | 2631篇 |
晶体学 | 28篇 |
力学 | 562篇 |
综合类 | 92篇 |
数学 | 2071篇 |
物理学 | 1686篇 |
出版年
2024年 | 5篇 |
2023年 | 46篇 |
2022年 | 111篇 |
2021年 | 131篇 |
2020年 | 150篇 |
2019年 | 151篇 |
2018年 | 141篇 |
2017年 | 161篇 |
2016年 | 217篇 |
2015年 | 130篇 |
2014年 | 245篇 |
2013年 | 446篇 |
2012年 | 341篇 |
2011年 | 304篇 |
2010年 | 310篇 |
2009年 | 339篇 |
2008年 | 330篇 |
2007年 | 400篇 |
2006年 | 342篇 |
2005年 | 332篇 |
2004年 | 278篇 |
2003年 | 295篇 |
2002年 | 220篇 |
2001年 | 189篇 |
2000年 | 176篇 |
1999年 | 159篇 |
1998年 | 125篇 |
1997年 | 108篇 |
1996年 | 98篇 |
1995年 | 86篇 |
1994年 | 122篇 |
1993年 | 77篇 |
1992年 | 82篇 |
1991年 | 54篇 |
1990年 | 43篇 |
1989年 | 41篇 |
1988年 | 35篇 |
1987年 | 33篇 |
1986年 | 30篇 |
1985年 | 42篇 |
1984年 | 27篇 |
1983年 | 11篇 |
1982年 | 21篇 |
1981年 | 11篇 |
1980年 | 14篇 |
1979年 | 10篇 |
1978年 | 13篇 |
1977年 | 6篇 |
1976年 | 11篇 |
1973年 | 6篇 |
排序方式: 共有7070条查询结果,搜索用时 8 毫秒
1.
Dean A. Carlson 《Journal of Mathematical Analysis and Applications》2002,276(2):561-588
The method of equivalent variational methods, originally due to Carathéodory for free problems in the calculus of variations is extended to investigate feedback Nash equilibria for a class of n-person differential games. Both the finite-horizon and infinite-horizon cases are considered. Examples are given to illustrate the presented results. 相似文献
2.
MC模式下顾客需求与厂商供应的纳什均衡 总被引:3,自引:0,他引:3
在大规模定制(MC,Mass Customization)模式下,基于市场需求的复杂化,厂商对个性化的顾客需求很难做出及时准确的反应,而且由于其自身生产能力的限制,不可能对所有的个性化用户进行一一地满足,只可能对已经存在的个性化需求,根据自身的生产能力和规模,以利润最大化及顾客对产品的满意度为目标,对个性化需求进行较准确地预测,从而正确指导生产。本通过博弈论的方法,提出了一个基于顾客对产品的满意度及企业的利润的一个非合作博弈模型,并给出求解纳什均衡的方法。 相似文献
3.
4.
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
5.
Yuh-Shan Ho 《Adsorption》2004,10(2):151-158
The kinetics of four sorption systems, Cu/tree fern, Pb/tree fern, AB9/activated clay and BR18/activated clay have been studied based on the assumption of a pseudo-second order rate law. Pseudo-isotherms using the pseudo-second order kinetic expression constant have been developed to describe the four liquid-solid sorption systems. The experimental results have been analyzed using a pseudo-Langmuir and a pseudo-Redlich-Peterson isotherm. Both isotherms were found to represent the measured sorption data well. According to the evaluation using the pseudo-Langmuir equation, the monolayer sorption capacities were obtained to be 13.9, 46.6, 124 and 105 mg g–1 for copper, lead, AB9 and BR18 respectively. 相似文献
6.
For vector quasivariational inequalities involving multifunctions in topological vector spaces, an existence result is obtained without a monotonicity assumption and with a convergence assumption weaker than semicontinuity. A new type of quasivariational inequality is proposed. Applications to quasicomplementarity problems and traffic network equilibria are considered. In particular, definitions of weak and strong Wardrop equilibria are introduced for the case of multivalued cost functions. 相似文献
7.
A carousel is a dynamical system that describes the movement of an equilateral linkage in which the midpoint of each rod travels parallel to it. They are closely related to the floating body problem. We prove, using the work of Auerbach, that any figure that floats in equilibrium in every position is drawn by a carousel. Of special interest are such figures with rational perimetral density of the floating chords, which are then drawn by carousels. In particular, we prove that for some perimetral densities the only such figure is the circle, as the problem suggests. 相似文献
8.
通过对非饱和土非线性本构方程和场方程的线性化,推导出了非饱和土的线性本构方程和场方程,把线性方程表示为与Biot饱和多孔介质方程相似的形式;证明了Darcy定律对非饱和土的适用性;说明了Biot饱和多孔介质方程是这些线性方程的特征。所有这些都表明用混合理论处理非饱和土本构问题的正确性。 相似文献
9.
L. A. Sakhnovich 《Functional Analysis and Its Applications》2002,36(3):205-211
The conjecture according to which the mean energy of an equilibrium system in quantum theory exceeds the mean energy of the corresponding classical system is considered. It is rigorously proved that the conjecture holds for the potential well. The estimates for the mean energy of the potential well at high and low temperatures are of special interest. 相似文献
10.
引入了随机环境中双移民生灭过程的概念,定义了过程的模态指示函数,在此基础上研究了其转移矩阵的平稳分布,给出了平稳分布众数的位置与模态指示函数之间的关系.研究了平稳分布的众数与边界关系. 相似文献