全文获取类型
收费全文 | 4370篇 |
免费 | 589篇 |
国内免费 | 510篇 |
专业分类
化学 | 1363篇 |
晶体学 | 61篇 |
力学 | 518篇 |
综合类 | 58篇 |
数学 | 1405篇 |
物理学 | 2064篇 |
出版年
2024年 | 3篇 |
2023年 | 43篇 |
2022年 | 90篇 |
2021年 | 73篇 |
2020年 | 96篇 |
2019年 | 99篇 |
2018年 | 100篇 |
2017年 | 129篇 |
2016年 | 190篇 |
2015年 | 172篇 |
2014年 | 224篇 |
2013年 | 363篇 |
2012年 | 276篇 |
2011年 | 303篇 |
2010年 | 236篇 |
2009年 | 311篇 |
2008年 | 303篇 |
2007年 | 323篇 |
2006年 | 318篇 |
2005年 | 207篇 |
2004年 | 210篇 |
2003年 | 200篇 |
2002年 | 167篇 |
2001年 | 137篇 |
2000年 | 142篇 |
1999年 | 123篇 |
1998年 | 123篇 |
1997年 | 89篇 |
1996年 | 69篇 |
1995年 | 61篇 |
1994年 | 45篇 |
1993年 | 30篇 |
1992年 | 39篇 |
1991年 | 24篇 |
1990年 | 25篇 |
1989年 | 17篇 |
1988年 | 15篇 |
1987年 | 7篇 |
1986年 | 11篇 |
1985年 | 17篇 |
1984年 | 10篇 |
1983年 | 4篇 |
1982年 | 13篇 |
1981年 | 12篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有5469条查询结果,搜索用时 15 毫秒
1.
Bifurcation analysis of visual angle model with anticipated time and stabilizing driving behavior
下载免费PDF全文
![点击此处可从《中国物理 B》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Xueyi Guan 《中国物理 B》2022,31(7):70507-070507
In the light of the visual angle model (VAM), an improved car-following model considering driver's visual angle, anticipated time and stabilizing driving behavior is proposed so as to investigate how the driver's behavior factors affect the stability of the traffic flow. Based on the model, linear stability analysis is performed together with bifurcation analysis, whose corresponding stability condition is highly fit to the results of the linear analysis. Furthermore, the time-dependent Ginzburg-Landau (TDGL) equation and the modified Korteweg-de Vries (mKdV) equation are derived by nonlinear analysis, and we obtain the relationship of the two equations through the comparison. Finally, parameter calibration and numerical simulation are conducted to verify the validity of the theoretical analysis, whose results are highly consistent with the theoretical analysis. 相似文献
2.
Yalda Liaghati Mobarhan Ronald Soong Daniel Lane Andre J. Simpson 《Magnetic resonance in chemistry : MRC》2020,58(5):427-444
Traditionally, due to different hardware requirements, nuclear magnetic resonance (NMR) has developed as two separate fields: one dealing with solids, and one with solutions. Comprehensive multiphase (CMP) NMR combines all electronics and hardware (magic angle spinning [MAS], gradients, high power Radio Frequency (RF) handling, lock, susceptibility matching) into a universal probe that permits a comprehensive study of all phases (i.e., liquid, gel-like, semisolid, and solid), in intact samples. When applied in vivo, it provides unique insight into the wide array of bonds in a living system from the most mobile liquids (blood, fluids) through gels (muscle, tissues) to the most rigid (exoskeleton, shell). In this tutorial, the practical aspects of in vivo CMP NMR are discussed including: handling the organisms, rotor preparation, sample spinning, water suppression, editing experiments, and finishes with a brief look at the potential of other heteronuclei (2H, 15N, 19F, 31P) for in vivo research. The tutorial is aimed as a general resource for researchers interested in developing and applying MAS-based approaches to living organisms. Although the focus here is CMP NMR, many of the approaches can be adapted (or directly applied) using conventional high-resolution magic angle spinning, and in some cases, even standard solid-state NMR probes. 相似文献
3.
4.
本文给出了C^n中子空间之间最大和最小主角在矩阵逼近,投影算子的扰动分析,群逆以及Oraxin逆的扰动估计,条件数理论,Bott-Duffin系统扰动分析中一些应用。 相似文献
5.
本文定义了二阶微分方程的弱 Carathéodory解 ,在不涉及紧型条件的情形下 ,直接用迭代法证明了 Banach空间二阶非线性常微分方程两点边值问题存在唯一解 ,并给出逼近解迭代序列的误差估计 ,对周期边值问题得到类似的结果 相似文献
6.
Ari Sihvola 《Optik》2006,117(7):317-320
A geometric visualization is presented for the Brewster angle for a plane wave reflecting from an interface. The surface is assumed to be isotropic but it is allowed to display both dielectric and magnetic susceptibility, and hence the Brewster (polarizing) angle can attain any value between 0 and 90°, and can exist for both parallel and perpendicular polarizations. The geometric construction (a tetrahedron) is spanned by the basic material parameters of the surface. The Brewster angle appears in one of the faces of the tetrahedron. 相似文献
7.
Daniel B. Szyld 《Numerical Algorithms》2006,42(3-4):309-323
Given an oblique projector P on a Hilbert space, i.e., an operator satisfying P
2=P, which is neither null nor the identity, it holds that ||P|| = ||I –P||. This useful equality, while not widely-known, has been proven repeatedly in the literature. Many published proofs are reviewed, and simpler ones are presented. 相似文献
8.
Mathematical economics has a long history and covers many interdisciplinary areas between mathematics and economics. At its center lies the theory of market equilibrium. The purpose of this expository article is to introduce mathematicians to price decentralization in general equilibrium theory. In particular, it concentrates on the role of positivity in the theory of convex economic analysis and the role of normal cones in the theory of non-convex economies. 相似文献
9.
非线性奇异边值问题的正解 总被引:1,自引:0,他引:1
路慧芹 《应用泛函分析学报》2002,4(3):217-221
利用锥映射的不动点指数定量,研究了一类非线性奇异边值问题多个正解的存在性问题。在构造的解的存在条件之下,证明了奇异边值问题至少有两个正解的存在性定理。 相似文献
10.
Khalid KOUFANY 《数学学报(英文版)》2006,22(5):1467-1472
Let Ω be a symmetric cone. In this note, we introduce Hilbert's projective metric on Ω in terms of Jordan algebras and we apply it to prove that, given a linear invertible transformation g such that g(Ω) = Ω and a real number p, |p| 〉 1, there exists a unique element x ∈ Ω satisfying g(x) = x^p. 相似文献