全文获取类型
收费全文 | 10976篇 |
免费 | 833篇 |
国内免费 | 1006篇 |
专业分类
化学 | 426篇 |
晶体学 | 5篇 |
力学 | 600篇 |
综合类 | 188篇 |
数学 | 9882篇 |
物理学 | 1714篇 |
出版年
2024年 | 13篇 |
2023年 | 111篇 |
2022年 | 129篇 |
2021年 | 148篇 |
2020年 | 261篇 |
2019年 | 272篇 |
2018年 | 236篇 |
2017年 | 300篇 |
2016年 | 294篇 |
2015年 | 235篇 |
2014年 | 483篇 |
2013年 | 838篇 |
2012年 | 476篇 |
2011年 | 555篇 |
2010年 | 526篇 |
2009年 | 697篇 |
2008年 | 795篇 |
2007年 | 784篇 |
2006年 | 648篇 |
2005年 | 644篇 |
2004年 | 516篇 |
2003年 | 514篇 |
2002年 | 418篇 |
2001年 | 361篇 |
2000年 | 318篇 |
1999年 | 315篇 |
1998年 | 291篇 |
1997年 | 282篇 |
1996年 | 212篇 |
1995年 | 131篇 |
1994年 | 115篇 |
1993年 | 93篇 |
1992年 | 77篇 |
1991年 | 83篇 |
1990年 | 63篇 |
1989年 | 51篇 |
1988年 | 46篇 |
1987年 | 34篇 |
1986年 | 40篇 |
1985年 | 69篇 |
1984年 | 42篇 |
1983年 | 29篇 |
1982年 | 38篇 |
1981年 | 39篇 |
1980年 | 30篇 |
1979年 | 42篇 |
1978年 | 40篇 |
1977年 | 25篇 |
1976年 | 24篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 609 毫秒
381.
382.
通过构造适当的非负鞅,将Doob鞅收敛定理应用于几乎处处收敛的研究,给出了一类非齐次树上马氏链场加权和滑动平均的若干强偏差定理. 相似文献
383.
We consider standing waves for 4‐superlinear Schrödinger–Kirchhoff equations in with potential indefinite in sign. The nonlinearity considered in this study satisfies a condition that is much weaker than the classical Ambrosetti–Rabinowitz condition. We obtain a nontrivial solution and, in the case of odd nonlinearity, an unbounded sequence of solutions via the Morse theory and the fountain theorem, respectively. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
384.
The Allen–Cahn equation, coupled with dynamic boundary conditions, has recently received a good deal of attention. The new issue of this paper is the setting of a rather general mass constraint, which may involve either the solution inside the domain or its trace on the boundary. The system of nonlinear partial differential equations can be formulated as a variational inequality. The presence of the constraint in the evolution process leads to additional terms in the equation and the boundary condition containing a suitable Lagrange multiplier. A well‐posedness result is proved for the related initial value problem. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
385.
Infinitely many homoclinic orbits for a class of second‐order damped differential equations
下载免费PDF全文
![点击此处可从《Mathematical Methods in the Applied Sciences》网站下载免费的PDF全文](/ch/ext_images/free.gif)
We investigate the existence and multiplicity of homoclinic orbits for the second‐order damped differential equations For Equation 1 where L(t) and W(t,u) are neither autonomous nor periodic in t. Under certain assumptions on g, L, and W, we get infinitely many homoclinic orbits for superquadratic, subquadratic and concave–convex nonlinearities cases by using fountain theorem and dual fountain theorem in critical point theory. These results generalize and improve some existing results in the literature. Copyright © 2015 JohnWiley & Sons, Ltd. 相似文献
386.
On existence and multiplicity of similarity solutions to a nonlinear differential equation arising in magnetohydrodynamic Falkner–Skan flow for decelerated flows
下载免费PDF全文
![点击此处可从《Mathematical Methods in the Applied Sciences》网站下载免费的PDF全文](/ch/ext_images/free.gif)
R. Naseri A. Malek R. A. Van Gorder 《Mathematical Methods in the Applied Sciences》2015,38(17):4272-4278
Previously, existence and uniqueness of a class of monotone similarity solutions for a nonlinear differential equation arising in magnetohydrodynamic Falkner–Skan flow were considered in the case of accelerating flows. It was shown that a solution satisfying certain monotonicity properties exists and is unique for the case of accelerated flows and some decelerated flows. In this paper, we show that solutions to the problem can exist for decelerated flows even when the monotonicity conditions do not hold. In particular, these types of solutions have nonmonotone second derivatives and are, hence, a distinct type of solution from those studied previously. By virtue of this result, the present paper demonstrates the existence of an important type of solution for decelerated flows. Importantly, we show that multiple solutions can exist for the case of strongly decelerated flows, and this occurs because of the fact that the solutions do not satisfy the aforementioned monotonicity requirements. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
387.
388.
Acceleration of self‐consistent field convergence in ab initio molecular dynamics simulation with multiconfigurational wave function
下载免费PDF全文
![点击此处可从《Journal of computational chemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The Lagrange interpolation of molecular orbital (LIMO) method, which reduces the number of self‐consistent field iterations in ab initio molecular dynamics simulations with the Hartree–Fock method and the Kohn–Sham density functional theories, is extended to the theory of multiconfigurational wave functions. We examine two types of treatments for the active orbitals that are partially occupied. The first treatment, as denoted by LIMO(C), is a simple application of the conventional LIMO method to the union of the inactive core and the active orbitals. The second, as denoted by LIMO(S), separately treats the inactive core and the active orbitals. Numerical tests to compare the two treatments clarify that LIMO(S) is superior to LIMO(C). Further applications of LIMO(S) to various systems demonstrate its effectiveness and robustness. © 2014 Wiley Periodicals, Inc. 相似文献
389.
390.
Mingzhong Li Chenwei Liu Chen Liang Jibin Li 《Journal of Dispersion Science and Technology》2014,35(3):397-402
In order to increase the present understanding of bimodal emulsion drop size distributions, systematic series of experiments have been carried out to investigate the effects of formulation variables on bimodal drop size distributions, and probability distribution functions were proposed to analyze the distribution. The results show that, the span of the drop size and Sauter mean diameter become larger when the dispersed phase volume fraction becomes higher and rotor speed becomes lower; the Frechet function represents the experimental data satisfactorily. The prediction model of Sauter mean diameter established by combining the prediction theory of the maximum stable drop diameter and experimental analysis results can fit the experimental data well. 相似文献