全文获取类型
收费全文 | 5387篇 |
免费 | 414篇 |
国内免费 | 339篇 |
专业分类
化学 | 210篇 |
晶体学 | 2篇 |
力学 | 26篇 |
综合类 | 144篇 |
数学 | 5443篇 |
物理学 | 315篇 |
出版年
2024年 | 23篇 |
2023年 | 103篇 |
2022年 | 181篇 |
2021年 | 133篇 |
2020年 | 205篇 |
2019年 | 231篇 |
2018年 | 219篇 |
2017年 | 205篇 |
2016年 | 125篇 |
2015年 | 90篇 |
2014年 | 180篇 |
2013年 | 471篇 |
2012年 | 193篇 |
2011年 | 297篇 |
2010年 | 301篇 |
2009年 | 449篇 |
2008年 | 391篇 |
2007年 | 279篇 |
2006年 | 323篇 |
2005年 | 227篇 |
2004年 | 205篇 |
2003年 | 176篇 |
2002年 | 165篇 |
2001年 | 157篇 |
2000年 | 141篇 |
1999年 | 141篇 |
1998年 | 117篇 |
1997年 | 81篇 |
1996年 | 47篇 |
1995年 | 53篇 |
1994年 | 42篇 |
1993年 | 29篇 |
1992年 | 28篇 |
1991年 | 15篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 16篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 14篇 |
1984年 | 13篇 |
1983年 | 3篇 |
1982年 | 13篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 2篇 |
排序方式: 共有6140条查询结果,搜索用时 15 毫秒
91.
Zoltán Buczolich Gunther Leobacher Alexander Steinicke 《Mathematische Nachrichten》2023,296(10):4778-4805
We construct a Hölder continuous function on the unit interval which coincides in uncountably (in fact continuum) many points with every function of total variation smaller than 1 passing through the origin. We conclude that this function has impermeable graph—one of the key concepts introduced in this paper—and we present further examples of functions both with permeable and impermeable graphs. Moreover, we show that typical (in the sense of Baire category) continuous functions have permeable graphs. The first example function is subsequently used to construct an example of a continuous function on the plane which is intrinsically Lipschitz continuous on the complement of the graph of a Hölder continuous function with impermeable graph, but which is not Lipschitz continuous on the plane. As another main result, we construct a continuous function on the unit interval which coincides in a set of Hausdorff dimension 1 with every function of total variation smaller than 1 which passes through the origin. 相似文献
92.
针对小管径两相流流动特性, 全新优化设计弧形对壁式电导传感器. 通过动态实验在获取传感器测量信号的基础上, 采用有限穿越可视图理论构建对应于不同流型的两相流复杂网络. 通过分析发现, 有限穿越可视图网络异速生长指数和网络平均度值的联合分布可实现对小管径两相流的流型辨识; 有限穿越可视图度分布曲线峰值可有效刻画与泡径大小分布相关的流动物理结构细节特征; 网络平均度值可表征流动结构的宏观特性; 网络异速生长指数对流体动力学复杂性十分敏感, 可揭示不同流型演化过程中的细节演化动力学特性. 两相流测量信号的有限穿越可视图分析为揭示两相流流型的形成及演化动力学机理提供了新途径.
关键词:
两相流
复杂网络
有限穿越可视图
网络异速生长指数 相似文献
93.
Reanalysis of the photoassociation spectrum of the weakly binding (6S1/2 + 6P3/2) lg 133Cs2 levels, reported in the previous study [J. Mol. Spectro. 255 (2009) 106], is performed by using a Lu-Fano graph coupled to the improved LeRoy- Bernstein formula including two additional modified terms. A more accurate coefficient (c3) is obtained for the leading long-range potential (-c3/R3) of a diatomic molecule. 相似文献
94.
Zhongzhi Zhang Shuigeng Zhou Tao Zou Lichao Chen Jihong Guan 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,60(2):259-264
We make a mapping from Sierpinski fractals to a new class
of networks, the incompatibility networks, which are scale-free,
small-world, disassortative, and maximal planar graphs. Some
relevant characteristics of the networks such as degree
distribution, clustering coefficient, average path length, and
degree correlations are computed analytically and found to be
peculiarly rich. The method of network representation can be applied
to some real-life systems making it possible to study the complexity
of real networked systems within the framework of complex network
theory. 相似文献
95.
96.
We study the spin squeezing property of weighted graph states,which can be used to improve sensitivity in interferometry.We study the time evolution of spin squeezing under local decoherence acting independently on each qubit.Based on the analysis,the spin squeezing of the weighted graph states is somehow robust in the presence of decoherence and the decoherence limit in the improvement of the interferometric sensitivity is still achievable.Furthermore,one can obtain the optimal improvement of sensitivity by tuning the weighted of each edges of the weighted graph state. 相似文献
97.
用Java实现网上结构图实验仿真 总被引:2,自引:0,他引:2
基于线性系统仿真的连接矩阵方法,用Java语言开发面向结构图的实验仿真程序,以Applet小应用程序的形式插入网页中运行,实现了信号与系统网上实验教学中的结构图实验仿真。经试用,程序在浏览器中运行正常,可以完成一般线性系统仿真,与以MATLAB,LABView等程序开发的实验仿真程序相比,该程序运行环境简单,几乎所有常用的Web浏览器都支持Java运行,不需另行安装相应组件。对于线性系统结构图,实现了所见即所得的图形化编程环境,具有较好的人机交互性。 相似文献
98.
Simple expressions of the reflection and transmission coefficients of fundamental Lamb waves by a rectangular notch 总被引:1,自引:0,他引:1
The scattering of Lamb waves by a two-dimensional rectangular notch is investigated for rapid inspection of defects in a structure. To derive the reflection and transmission coefficients of the scattered waves in a simple way, the scattering caused by the notch is analyzed through the composition of individual scattering processes. Linear equations corresponding to the reflection and transmission coefficients are constructed along with scattering graphs. For an illustration of the efficacy of the presented method, the scattering of fundamental symmetric and anti-symmetric modes are inspected according to the depth and width of a notch in a plate. Validity of these expressions is demonstrated by the comparison of the theoretical analysis results with those from the finite element analysis. 相似文献
99.
Exponential networked synchronization of master-slave chaotic systems with time-varying communication topologies 下载免费PDF全文
The networked synchronization problem of a class of master-slave chaotic systems with time-varying communication topologies is investigated in this paper. Based on algebraic graph theory and matrix theory, a simple linear state feedback controller is designed to synchronize the master chaotic system and the slave chaotic systems with a time- varying communication topology connection. The exponential stability of the closed-loop networked synchronization error system is guaranteed by applying Lyapunov stability theory. The derived novel criteria are in the form of linear matrix inequalities (LMIs), which are easy to examine and tremendously reduce the computation burden from the feedback matrices. This paper provides an alternative networked secure communication scheme which can be extended conveniently. An illustrative example is given to demonstrate the effectiveness of the proposed networked synchronization method. 相似文献
100.
SHANG Yi-Lun 《理论物理通讯》2012,57(4):701-716
In this paper,we study a long-range percolation model on the lattice Z d with multi-type vertices and directed edges.Each vertex x ∈ Z d is independently assigned a non-negative weight Wx and a type ψx,where(Wx) x∈Z d are i.i.d.random variables,and(ψx) x∈Z d are also i.i.d.Conditionally on weights and types,and given λ,α 0,the edges are independent and the probability that there is a directed edge from x to y is given by pxy = 1 exp(λφψ x ψ y WxWy /| x-y | α),where φij 's are entries from a type matrix Φ.We show that,when the tail of the distribution of Wx is regularly varying with exponent τ-1,the tails of the out/in-degree distributions are both regularly varying with exponent γ = α(τ-1) /d.We formulate conditions under which there exist critical values λ WCC c ∈(0,∞) and λ SCC c ∈(0,∞) such that an infinite weak component and an infinite strong component emerge,respectively,when λ exceeds them.A phase transition is established for the shortest path lengths of directed and undirected edges in the infinite component at the point γ = 2,where the out/in-degrees switch from having finite to infinite variances.The random graph model studied here features some structures of multi-type vertices and directed edges which appear naturally in many real-world networks,such as the SNS networks and computer communication networks. 相似文献