全文获取类型
收费全文 | 41043篇 |
免费 | 6474篇 |
国内免费 | 5686篇 |
专业分类
化学 | 31234篇 |
晶体学 | 562篇 |
力学 | 2173篇 |
综合类 | 454篇 |
数学 | 4537篇 |
物理学 | 14243篇 |
出版年
2024年 | 31篇 |
2023年 | 698篇 |
2022年 | 883篇 |
2021年 | 1218篇 |
2020年 | 1600篇 |
2019年 | 1641篇 |
2018年 | 1308篇 |
2017年 | 1376篇 |
2016年 | 1830篇 |
2015年 | 1818篇 |
2014年 | 2389篇 |
2013年 | 3140篇 |
2012年 | 3812篇 |
2011年 | 4042篇 |
2010年 | 3005篇 |
2009年 | 2753篇 |
2008年 | 2984篇 |
2007年 | 2678篇 |
2006年 | 2564篇 |
2005年 | 2183篇 |
2004年 | 1638篇 |
2003年 | 1344篇 |
2002年 | 1285篇 |
2001年 | 1036篇 |
2000年 | 898篇 |
1999年 | 779篇 |
1998年 | 575篇 |
1997年 | 512篇 |
1996年 | 465篇 |
1995年 | 452篇 |
1994年 | 391篇 |
1993年 | 324篇 |
1992年 | 289篇 |
1991年 | 257篇 |
1990年 | 232篇 |
1989年 | 177篇 |
1988年 | 143篇 |
1987年 | 81篇 |
1986年 | 88篇 |
1985年 | 90篇 |
1984年 | 37篇 |
1983年 | 33篇 |
1982年 | 37篇 |
1981年 | 21篇 |
1980年 | 11篇 |
1979年 | 15篇 |
1973年 | 3篇 |
1971年 | 6篇 |
1957年 | 10篇 |
1936年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
1.
2.
Science China Mathematics - This paper studies exact synchronization and asymptotic synchronization problems for a controlled linear system of ordinary differential equations. In this paper, we... 相似文献
3.
4.
Hu Duo-Duo Gao Qian Dai Jing-Cheng Cui Ru Li Yuan-Bo Li Yuan-Ming Zhou Xiao-Guo Bian Kang-Jie Wu Bing-Bing Zhang Kai-Fan Wang Xi-Sheng Li Yan 《中国科学:化学(英文版)》2022,65(4):753-761
Science China Chemistry - A light-induced, nickel-catalyzed three-component arylsulfonation of 1,3-enynes in the absence of photocatalyst is reported. This methodology exhibited mild conditions,... 相似文献
6.
The Random Batch Method proposed in our previous work(Jin et al.J Comput Phys,2020)is not only a numerical method for interacting particle systems and its mean-field limit,but also can be viewed as a model of the particle system in which particles interact,at discrete time,with randomly selected mini-batch of particles.In this paper,we investigate the mean-field limit of this model as the number of particles N→∞.Unlike the classical mean field limit for interacting particle systems where the law of large numbers plays the role and the chaos is propagated to later times,the mean field limit now does not rely on the law of large numbers and the chaos is imposed at every discrete time.Despite this,we will not only justify this mean-field limit(discrete in time)but will also show that the limit,as the discrete time intervalτ→0,approaches to the solution of a nonlinear Fokker-Planck equation arising as the mean-field limit of the original interacting particle system in the Wasserstein distance. 相似文献
7.
Given a graph sequence denote by T3(Gn) the number of monochromatic triangles in a uniformly random coloring of the vertices of Gn with colors. In this paper we prove a central limit theorem (CLT) for T3(Gn) with explicit error rates, using a quantitative version of the martingale CLT. We then relate this error term to the well-known fourth-moment phenomenon, which, interestingly, holds only when the number of colors satisfies . We also show that the convergence of the fourth moment is necessary to obtain a Gaussian limit for any , which, together with the above result, implies that the fourth-moment condition characterizes the limiting normal distribution of T3(Gn), whenever . Finally, to illustrate the promise of our approach, we include an alternative proof of the CLT for the number of monochromatic edges, which provides quantitative rates for the results obtained in [7]. 相似文献
8.
In this paper,we investigate the non-autonomous Hamilton-Jacobi equation ■ where H is 1-periodic with respect to t and M is a compact Riemannian manifold without boundary.We obtain the viscosity solution denoted by T_(t_0)~tφ(x) and show T_(t_0)~tφ(x) converges uniformly to a time-periodic viscosity solution u~*(x,t) of ?_tu+H(t,x,?_xu,u)=0. 相似文献
9.
Zhao Tianqi Luo Tianzi Fang Bo Shi Lijiang Jin Yongxing Zhou Pengwei Yao Dong Li Chenxia Jing Xufeng Hong Zhi 《Journal of Russian Laser Research》2021,42(5):586-597
Journal of Russian Laser Research - The zero-refractive-index metamaterials have excellent electromagnetic properties, which provide new ideas and methods to realize the control of electromagnetic... 相似文献
10.
Applied Mathematics and Mechanics - A consequence of nonlinearities is a multi-harmonic response via a mono-harmonic excitation. A similar phenomenon also exists in random vibration. The power... 相似文献