全文获取类型
收费全文 | 204253篇 |
免费 | 33411篇 |
国内免费 | 23387篇 |
专业分类
化学 | 138338篇 |
晶体学 | 2413篇 |
力学 | 13316篇 |
综合类 | 1545篇 |
数学 | 27369篇 |
物理学 | 78070篇 |
出版年
2024年 | 200篇 |
2023年 | 3626篇 |
2022年 | 4254篇 |
2021年 | 6208篇 |
2020年 | 7827篇 |
2019年 | 7506篇 |
2018年 | 6837篇 |
2017年 | 6373篇 |
2016年 | 9586篇 |
2015年 | 9303篇 |
2014年 | 11442篇 |
2013年 | 15337篇 |
2012年 | 18185篇 |
2011年 | 19190篇 |
2010年 | 13336篇 |
2009年 | 12931篇 |
2008年 | 13786篇 |
2007年 | 12453篇 |
2006年 | 11594篇 |
2005年 | 9870篇 |
2004年 | 7567篇 |
2003年 | 6089篇 |
2002年 | 5287篇 |
2001年 | 4535篇 |
2000年 | 3878篇 |
1999年 | 4159篇 |
1998年 | 3576篇 |
1997年 | 3240篇 |
1996年 | 3366篇 |
1995年 | 2924篇 |
1994年 | 2731篇 |
1993年 | 2257篇 |
1992年 | 2010篇 |
1991年 | 1812篇 |
1990年 | 1459篇 |
1989年 | 1131篇 |
1988年 | 900篇 |
1987年 | 743篇 |
1986年 | 727篇 |
1985年 | 601篇 |
1984年 | 453篇 |
1983年 | 322篇 |
1982年 | 267篇 |
1981年 | 205篇 |
1980年 | 149篇 |
1979年 | 79篇 |
1978年 | 62篇 |
1976年 | 79篇 |
1975年 | 78篇 |
1974年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Xu Yifan Zhang Hehe Ding Tangjing Tian Ruiqi Sun Dongmei Wang Ming-Sheng Zhou Xiaosi 《中国科学:化学(英文版)》2022,65(9):1807-1816
Science China Chemistry - Due to their enormous potential for large-scale energy storage, rechargeable potassium-ion batteries have been widely researched and developed. However, the drastic volume... 相似文献
32.
33.
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
34.
Thermoelectric(TE)energy harvesting can effectively convert waste heat into electricity,which is a crucial technology to solve energy concerns.As a promising candidate for energy conversion,poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)has gained significant attention owing to its easy doping,high transparency,and solution processability.However,the TE performance of PEDOT:PSS still needs to be further enhanced.Herein,different approaches have been applied for tuning the TE properties:(i)direct dipping PEDOT:PSS thin films in ionic liquid;(ii)post-treatment of the films with concentrated sulfuric acid(H2SO4),and then dipping in ionic liquid.Besides,the same bis(trifluoromethanesulfonyl)amide(TFSI)anion and different cation salts,including 1-ethyl-3-methylimidazolium(EMIM+)and lithium(Li+),are selected to study the influence of varying cation types on the TE properties of PEDOT:PSS.The Seebeck coefficient and electrical conductivity of the PEDOT:PSS film treated with H2SO4EMIM:TFSI increase simultaneously,and the resulting maximum power factor is 46.7μW·m-1·K-2,which may be attributed to the ionic liquid facilitating the rearrangement of the molecular chain of PEDOT.The work provides a reference for the development of organic films with high TE properties. 相似文献
35.
Theoretical and Mathematical Physics - We theoretically calculate general higher-order soliton solutions of the space-shifted parity–time-symmetric nonlocal multicomponent nonlinear... 相似文献
36.
Nonlinear Dynamics - This paper proposes an output feedback control strategy to achieve the global regulation of a class of large-scale feedforward nonlinear systems with discrete and distributed... 相似文献
37.
Science China Mathematics - In this paper, we obtain a necessary and sufficient condition for a U(n)-invariant complex Finsler metric F on domains in ?n to be strongly convex, which also... 相似文献
38.
39.
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
40.
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