全文获取类型
收费全文 | 284篇 |
免费 | 25篇 |
国内免费 | 14篇 |
专业分类
化学 | 6篇 |
晶体学 | 2篇 |
力学 | 52篇 |
综合类 | 15篇 |
数学 | 216篇 |
物理学 | 32篇 |
出版年
2024年 | 6篇 |
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 6篇 |
2020年 | 17篇 |
2019年 | 12篇 |
2018年 | 5篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 8篇 |
2014年 | 14篇 |
2013年 | 20篇 |
2012年 | 4篇 |
2011年 | 13篇 |
2010年 | 7篇 |
2009年 | 9篇 |
2008年 | 14篇 |
2007年 | 9篇 |
2006年 | 9篇 |
2005年 | 14篇 |
2004年 | 12篇 |
2003年 | 13篇 |
2002年 | 16篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 12篇 |
1998年 | 19篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 13篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有323条查询结果,搜索用时 15 毫秒
31.
32.
33.
This paper derives a theorem of generalized singular value decomposition of quaternion matrices(QGSVD),studies the solution of general quaternion matrix equation AXB-CYD=E,and obtains quaternionic Roth's theorem.This paper also suggestssufficient and necessary conditions for the existence and uniqueness of solutions and explicit forms of the solutions of the equation. 相似文献
34.
基于最优控制的四元数据误差传播捷联矩阵算法分析 总被引:1,自引:0,他引:1
捷联系统中的比力、角速率的量测值都是沿船舶坐标系的,如欲求得船舶位置和姿态就应知道其在当地地理坐标系中的投影。无论从计算速度还是从计算精度上考虑,用四元数法得到捷联短阵比其他方法更为有利。该就四元数计算所引起的误差及其传播方式与四元数向量的正交计算进行了讨论,从而获得了一种捷联矩阵算法。 相似文献
35.
为了描述编队卫星中主从星的相对位置和姿态信息,提出了基于对偶四元数的编队卫星相对位姿测量算法。以双星编队飞行的位姿运动为主线,运用对偶四元数工具,充分发挥其能以最简洁的形式表示一般性刚体运动的优点,对卫星轨道和姿态进行分析并建立了对偶四元数位姿模型。同时设计类GPS测量技术来测量编队卫星的相对位置和姿态,该技术载波相位波长和伪码码元比GPS的更短,可获得更高精度的相对测量信号。由于状态方程和观测方程的非线性特征,使用UKF滤波来消除随机噪声对量测过程的干扰。实验结果表明,所设计的算法能够有效估计系统误差,卫星的位置误差和四元数误差收敛于零,验证了该算法的有效性。 相似文献
36.
In this paper, we consider a class of delayed quaternion‐valued cellular neural networks (DQVCNNs) with impulsive effects. By using a novel continuation theorem of coincidence degree theory, the existence of anti‐periodic solutions for DQVCNNs is obtained with or without assuming that the activation functions are bounded. Furthermore, by constructing a suitable Lyapunov function, some sufficient conditions are derived to guarantee the global exponential stability of anti‐periodic solutions for DQVCNNs. Our results are new and complementary to the known results even when DQVCNNs degenerate into real‐valued or complex‐valued neural networks. Finally, an example is given to illustrate the effectiveness of the obtained results. 相似文献
37.
《Mathematical Methods in the Applied Sciences》2018,41(12):4491-4505
A map is an involution (resp, anti‐involution) if it is a self‐inverse homomorphism (resp, antihomomorphism) of a field algebra. The main purpose of this paper is to show how split semi‐quaternions can be used to express half‐turn planar rotations in 3‐dimensional Euclidean space and how they can be used to express hyperbolic‐isoclinic rotations in 4‐dimensional semi‐Euclidean space . We present an involution and an anti‐involution map using split semi‐quaternions and give their geometric interpretations as half‐turn planar rotations in . Also, we give the geometric interpretation of nonpure unit split semi‐quaternions, which are in the form p = coshθ + sinhθ i + 0 j + 0 k = coshθ + sinhθ i , as hyperbolic‐isoclinic rotations in . 相似文献
38.
39.
The set of hybrid numbers is a noncommutative number system that unified and generalized the complex, dual, and double (hyperbolic) numbers with the relation ih =− hi =ε+ i. Two hybrid numbers p and q are said to be similar if there exist a nonlightlike hybrid number x satisfying the equality x −1 qx = p . And, it is denoted by p ∼ q . In this paper, we study the concept of similarity for hybrid numbers by solving the linear equations px = xq and qx − xp = c for 相似文献
40.
Gang Wang Zhenwei Guo Dong Zhang Tongsong Jiang 《Mathematical Methods in the Applied Sciences》2020,43(3):1124-1137
This paper aims to present, in a unified manner, algebraic techniques for least squares problem in quaternionic and split quaternionic mechanics. This paper, by means of a complex representation and a real representation of a generalized quaternion matrix, studies generalized quaternion least squares (GQLS) problem, and derives two algebraic methods for solving the GQLS problem. This paper gives not only algebraic techniques for least squares problem over generalized quaternion algebras, but also a unification of algebraic techniques for least squares problem in quaternionic and split quaternionic theory. 相似文献