全文获取类型
收费全文 | 10914篇 |
免费 | 1321篇 |
国内免费 | 1153篇 |
专业分类
化学 | 5111篇 |
晶体学 | 48篇 |
力学 | 514篇 |
综合类 | 49篇 |
数学 | 908篇 |
物理学 | 2962篇 |
综合类 | 3796篇 |
出版年
2024年 | 41篇 |
2023年 | 216篇 |
2022年 | 311篇 |
2021年 | 338篇 |
2020年 | 325篇 |
2019年 | 333篇 |
2018年 | 264篇 |
2017年 | 305篇 |
2016年 | 406篇 |
2015年 | 467篇 |
2014年 | 472篇 |
2013年 | 579篇 |
2012年 | 763篇 |
2011年 | 851篇 |
2010年 | 597篇 |
2009年 | 549篇 |
2008年 | 676篇 |
2007年 | 598篇 |
2006年 | 539篇 |
2005年 | 485篇 |
2004年 | 409篇 |
2003年 | 316篇 |
2002年 | 278篇 |
2001年 | 251篇 |
2000年 | 220篇 |
1999年 | 382篇 |
1998年 | 278篇 |
1997年 | 316篇 |
1996年 | 301篇 |
1995年 | 257篇 |
1994年 | 215篇 |
1993年 | 177篇 |
1992年 | 136篇 |
1991年 | 148篇 |
1990年 | 141篇 |
1989年 | 121篇 |
1988年 | 109篇 |
1987年 | 68篇 |
1986年 | 53篇 |
1985年 | 36篇 |
1984年 | 14篇 |
1983年 | 11篇 |
1982年 | 14篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1957年 | 3篇 |
1955年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Cuixia Cui Yong Gao Dr. Jun Li Chao Yang Meng Liu Prof. Dr. Huile Jin Prof. Dr. Zhenhai Xia Prof. Dr. Liming Dai Prof. Dr. Yong Lei Prof. Dr. Jichang Wang Prof. Dr. Shun Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(20):8002-8007
Although tremendous efforts have been devoted to understanding the origin of boosted charge storage on heteroatom-doped carbons, none of the present studies has shown a whole landscape. Herein, by both experimental evidence and theoretical simulation, it is demonstrated that heteroatom doping not only results in a broadened operating voltage, but also successfully promotes the specific capacitance in aqueous supercapacitors. In particular, the electrolyte cations adsorbed on heteroatom-doped carbon can effectively inhibit hydrogen evolution reaction, a key step of water decomposition during the charging process, which broadens the voltage window of aqueous electrolytes even beyond the thermodynamic limit of water (1.23 V). Furthermore, the reduced adsorption energy of heteroatom-doped carbon consequently leads to more stored cations on the heteroatom-doped carbon surface, thus yielding a boosted charge storage performance. 相似文献
3.
4.
5.
戴桂生 《苏州大学学报(医学版)》1992,8(2):120-123
In this paper, we obtain a theorem for the classification of the irreducible Harich-Chandra modules over G, Where G is a basic classical Lie superalgebra of I type. And the list of the classi-ficatication is given for G=A(1,0). 相似文献
6.
三峡库区移民区曲溪小流域能源利用分析 总被引:1,自引:0,他引:1
通过分析小流域的能源资源现状、不同时期能源需求变化对生态环境的影响、秸秆利用对坡耕地生产力的影响、经济发展对生物质能需求影响、节能及替代能源对生物质能需求的影响等,提出了解决能源问题,促进生态环境持续改善的对策. 相似文献
7.
8.
Inspired by the recent work [HHM03], we prove two stability results for compact Riemannian manifolds with nonzero parallel spinors. Our first result says that Ricci flat metrics which also admit nonzero parallel spinors are stable (in the direction of changes in conformal structures) as the critical points of the total scalar curvature functional. Our second result, which is a local version of the first one, shows that any metric of positive scalar curvature cannot lie too close to a metric with nonzero parallel spinor. We also prove a rigidity result for special holonomy metrics. In the case of SU(m) holonomy, the rigidity result implies that scalar flat deformations of Calabi-Yau metric must be Calabi-Yau. Finally we explore the connection with a positive mass theorem of [D03], which presents another approach to proving these stability and rigidity results. Dedicated to Jeff Cheeger for his sixtieth birthday 相似文献
9.
In-time motion adjustment in laser cladding manufacturing process for improving dimensional accuracy and surface finish of the formed part 总被引:2,自引:0,他引:2
This paper presents in-time motion adjustment in laser cladding manufacturing process as a means to improve dimensional accuracy and surface finish of the built part. Defects occurring during laser cladding degrade the part quality such as dimensional accuracy and surface finish. In this paper, in-time motion adjustment strategy was presented to remedy and eliminate defects occurring during laser cladding to improve the dimensional accuracy and surface finish. Based on the relationship between the motion of laser head relative to the growing part and other parameters in effects on clad profile, the laser traverse speed, stand-off distance and laser approach orientation to the existing clad layer were adjusted by instructions from a close-loop control system in real time to remedy and eliminate defects. The results of the experiments verified the effects of in-time motion adjustment on dimensional accuracy and surface finish. 相似文献
10.
将自卫机制加入OOP成为AOP以提高CORBA中软件的强健性和防卫能力,在CORBA这个异构环境中,一个对象申请服务之后就需等待,如果应答迟迟不到则有可能永远等待下去,为避免这种现象的产生和蔓延,在客户和服务方的行为中加入超时机制(timeout mecha-nism)并采用利己或利他策略,使得对象可独立地根据当前环境和时间决定下一步骤,将这种在协作者失败的情况下仍能生存的对象称为自卫智能体,加入白卫智能体的CORBA称为CORBA~( ),由于智能体可在任何条件下生存,CORBA~( )可为用户提供可靠的服务,也就能实现CORBA~( )中软件构成的强健性。 相似文献