全文获取类型
收费全文 | 9491篇 |
免费 | 1115篇 |
国内免费 | 952篇 |
专业分类
化学 | 233篇 |
晶体学 | 1篇 |
力学 | 882篇 |
综合类 | 203篇 |
数学 | 8469篇 |
物理学 | 1770篇 |
出版年
2024年 | 10篇 |
2023年 | 76篇 |
2022年 | 80篇 |
2021年 | 117篇 |
2020年 | 198篇 |
2019年 | 213篇 |
2018年 | 243篇 |
2017年 | 287篇 |
2016年 | 329篇 |
2015年 | 228篇 |
2014年 | 385篇 |
2013年 | 685篇 |
2012年 | 413篇 |
2011年 | 483篇 |
2010年 | 433篇 |
2009年 | 549篇 |
2008年 | 649篇 |
2007年 | 614篇 |
2006年 | 617篇 |
2005年 | 545篇 |
2004年 | 512篇 |
2003年 | 469篇 |
2002年 | 462篇 |
2001年 | 356篇 |
2000年 | 410篇 |
1999年 | 311篇 |
1998年 | 285篇 |
1997年 | 292篇 |
1996年 | 190篇 |
1995年 | 183篇 |
1994年 | 135篇 |
1993年 | 124篇 |
1992年 | 99篇 |
1991年 | 80篇 |
1990年 | 68篇 |
1989年 | 37篇 |
1988年 | 43篇 |
1987年 | 30篇 |
1986年 | 34篇 |
1985年 | 29篇 |
1984年 | 36篇 |
1983年 | 13篇 |
1982年 | 29篇 |
1981年 | 20篇 |
1980年 | 24篇 |
1979年 | 24篇 |
1978年 | 29篇 |
1977年 | 26篇 |
1975年 | 9篇 |
1974年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
Applied Mathematics and Mechanics - Mechanical models of residually stressed fibre-reinforced solids, which do not resist bending, have been developed in the literature. However, in some residually... 相似文献
3.
Hasan Kara Muhammad Aamir Ali Hüseyin Budak 《Mathematical Methods in the Applied Sciences》2021,44(1):104-123
In this paper, we define interval‐valued left‐sided and right‐sided generalized fractional double integrals. We establish inequalities of Hermite‐Hadamard like for coordinated interval‐valued convex functions by applying our newly defined integrals. 相似文献
4.
This work is concerned with the extension of the Jacobi spectral Galerkin method to a class of nonlinear fractional pantograph differential equations. First, the fractional differential equation is converted to a nonlinear Volterra integral equation with weakly singular kernel. Second, we analyze the existence and uniqueness of solutions for the obtained integral equation. Then, the Galerkin method is used for solving the equivalent integral equation. The error estimates for the proposed method are also investigated. Finally, illustrative examples are presented to confirm our theoretical analysis. 相似文献
5.
In this paper, we propose a mechanism on how to construct long MDS self-dual codes from short ones. These codes are special types of generalized Reed-Solomon (GRS) codes or extended generalized Reed-Solomon codes. The main tool is utilizing additive structure or multiplicative structure on finite fields. By applying this method, more MDS self-dual codes can be constructed. 相似文献
6.
7.
Yuhua Long 《Journal of Difference Equations and Applications》2020,26(7):966-986
In the present paper, we apply the method of invariant sets of descending flow to establish a series of criteria to ensure that a second-order nonlinear functional difference equation with periodic boundary conditions possesses at least one trivial solution and three nontrivial solutions. These nontrivial solutions consist of sign-changing solutions, positive solutions and negative solutions. Moreover, as an application of our theoretical results, an example is elaborated. Our results generalize and improve some existing ones. 相似文献
8.
Sutapa Saha Some Sankar Bhattacharya Tamal Guha Saronath Halder Manik Banik 《Annalen der Physik》2020,532(12):2000334
Quantum correlations provide dramatic advantage over the corresponding classical resources in several communication tasks. However, a broad class of probabilistic theories exists that attributes greater success than quantum theory in many of these tasks by allowing supra-quantum correlations in “space-like” and/or “time-like” paradigms. In this letter, a communication task involving three spatially separated parties is proposed where one party (verifier) aims to verify whether the bit strings possessed by the other two parties (terminals) are equal or not. This task is called authentication with limited communication, the restrictions on communication being: i) the terminals cannot communicate with each other, but (ii) each of them can communicate with the verifier through single use of channels with limited capacity. Manifestly, classical resources are not sufficient for perfect success of this task. Moreover, it is also not possible to perform this task with certainty in several nonclassical theories although they might possess stronger “space-like” and/or “time-like” correlations. Surprisingly, quantum resources can achieve the perfect winning strategy. The proposed task thus stands apart from all previously known communication tasks as it exhibits quantum advantage over other nonclassical strategies. 相似文献
9.
10.
Nonlinear effects such as friction and freeplay on the control surfaces can affect aeroelastic dynamics during flight. In particular, these nonlinearities can induce limit cycle oscillations (LCO), changing the system stability, and because of this it is essential to employ computational methods to predict this type of motion during the aircraft development cycle. In this context, the present article presents a matrix notation for describing the Hénon’s method used to reduce errors when considering piecewise linear nonlinearities in the numerical integration process. In addition, a new coordinate system is used to write the aeroelastic system of equations. The proposal defines a displacement vector with generalized and physical variables to simplify the computational implementation of the Hénon’s technique. Additionally, the article discusses the influence of asymmetric freeplay and friction on the LCO of an airfoil with control surface. The results show that the extended Hénon’s technique provides more accurate LCO predictions, that friction can change the frequency and amplitude of these motions, and the asymmetry of freeplay is important to determine the LCO behavior. 相似文献