全文获取类型
收费全文 | 7427篇 |
免费 | 1190篇 |
国内免费 | 973篇 |
专业分类
化学 | 5109篇 |
晶体学 | 48篇 |
力学 | 514篇 |
综合类 | 49篇 |
数学 | 908篇 |
物理学 | 2962篇 |
出版年
2024年 | 18篇 |
2023年 | 153篇 |
2022年 | 246篇 |
2021年 | 245篇 |
2020年 | 278篇 |
2019年 | 299篇 |
2018年 | 227篇 |
2017年 | 234篇 |
2016年 | 344篇 |
2015年 | 367篇 |
2014年 | 360篇 |
2013年 | 464篇 |
2012年 | 655篇 |
2011年 | 715篇 |
2010年 | 471篇 |
2009年 | 389篇 |
2008年 | 504篇 |
2007年 | 440篇 |
2006年 | 415篇 |
2005年 | 383篇 |
2004年 | 324篇 |
2003年 | 228篇 |
2002年 | 193篇 |
2001年 | 170篇 |
2000年 | 125篇 |
1999年 | 185篇 |
1998年 | 126篇 |
1997年 | 136篇 |
1996年 | 146篇 |
1995年 | 132篇 |
1994年 | 90篇 |
1993年 | 74篇 |
1992年 | 66篇 |
1991年 | 66篇 |
1990年 | 71篇 |
1989年 | 57篇 |
1988年 | 44篇 |
1987年 | 28篇 |
1986年 | 35篇 |
1985年 | 29篇 |
1984年 | 14篇 |
1983年 | 10篇 |
1982年 | 14篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1957年 | 3篇 |
排序方式: 共有9590条查询结果,搜索用时 31 毫秒
2.
3.
4.
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
5.
6.
7.
Shaobo Cheng Vidushi Sharma Altug S. Poyraz Lijun Wu Xing Li Amy C. Marschilok Esther S. Takeuchi Kenneth J. Takeuchi Marivi Fernndez-Serra Yimei Zhu 《Chemical science》2020,11(19):4991
Tunneled metal oxides such as α-Mn8O16 (hollandite) have proven to be compelling candidates for charge-storage materials in high-density batteries. In particular, the tunnels can support one-dimensional chains of K+ ions (which act as structure-stabilizing dopants) and H2O molecules, as these chains are favored by strong H-bonds and electrostatic interactions. In this work, we examine the role of water molecules in enhancing the stability of K+-doped α-Mn8O16 (cryptomelane). The combined experimental and theoretical analyses show that for high enough concentrations of water and tunnel-ions, H2O displaces K+ ions from their natural binding sites. This displacement becomes energetically favorable due to the formation of K2+ dimers, thereby modifying the stoichiometric charge of the system. These findings have potentially significant technological implications for the consideration of cryptomelane as a Li+/Na+ battery electrode. Our work establishes the functional role of water in altering the energetics and structural properties of cryptomelane, an observation that has frequently been overlooked in previous studies.Water displaces potassium ions and initiates the formation of a homonuclear dimer ion (K2+) in the tunnels of hollandite. 相似文献
8.
Summary. Let be a square matrix dependent on parameters and , of which we choose as the eigenvalue parameter. Many computational problems are equivalent to finding a point such that has a multiple eigenvalue at . An incomplete decomposition of a matrix dependent on several parameters is proposed. Based on the developed theory two new algorithms are
presented for computing multiple eigenvalues of with geometric multiplicity . A third algorithm is designed for the computation of multiple eigenvalues with geometric multiplicity but which also appears to have local quadratic convergence to semi-simple eigenvalues. Convergence analyses of these methods
are given. Several numerical examples are presented which illustrate the behaviour and applications of our methods.
Received December 19, 1994 / Revised version received January 18, 1996 相似文献
9.
10.