全文获取类型
收费全文 | 100234篇 |
免费 | 4141篇 |
国内免费 | 2961篇 |
专业分类
化学 | 40095篇 |
晶体学 | 1060篇 |
力学 | 8021篇 |
综合类 | 239篇 |
数学 | 34342篇 |
物理学 | 23579篇 |
出版年
2024年 | 41篇 |
2023年 | 491篇 |
2022年 | 674篇 |
2021年 | 762篇 |
2020年 | 974篇 |
2019年 | 890篇 |
2018年 | 10976篇 |
2017年 | 10777篇 |
2016年 | 7009篇 |
2015年 | 1805篇 |
2014年 | 1515篇 |
2013年 | 1915篇 |
2012年 | 5769篇 |
2011年 | 12408篇 |
2010年 | 6956篇 |
2009年 | 7299篇 |
2008年 | 8013篇 |
2007年 | 10030篇 |
2006年 | 1536篇 |
2005年 | 2352篇 |
2004年 | 2358篇 |
2003年 | 2659篇 |
2002年 | 1608篇 |
2001年 | 754篇 |
2000年 | 795篇 |
1999年 | 739篇 |
1998年 | 674篇 |
1997年 | 570篇 |
1996年 | 629篇 |
1995年 | 501篇 |
1994年 | 431篇 |
1993年 | 417篇 |
1992年 | 321篇 |
1991年 | 291篇 |
1990年 | 284篇 |
1989年 | 217篇 |
1988年 | 177篇 |
1987年 | 141篇 |
1986年 | 154篇 |
1985年 | 111篇 |
1984年 | 79篇 |
1983年 | 75篇 |
1982年 | 78篇 |
1981年 | 59篇 |
1980年 | 54篇 |
1979年 | 48篇 |
1914年 | 45篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 930 毫秒
31.
32.
33.
Experimental Mechanics - There have been relatively few studies on mechanical properties of nanomaterials under high strain rates, mainly due to the lack of capable nanomechanical testing devices.... 相似文献
34.
Zenon Moszner 《Aequationes Mathematicae》2018,92(4):617-625
We give the form of the output function in Ginsburg’s machine in which the input and output dictionaries are abelian groups and the transition function is of a special form. 相似文献
35.
36.
37.
Yaping Chen Dr. Kun Rui Prof. Jixin Zhu Prof. Shi Xue Dou Dr. Wenping Sun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(3):703-713
Developing clean and sustainable energies as alternatives to fossil fuels is in strong demand within modern society. The oxygen evolution reaction (OER) is the efficiency-limiting process in plenty of key renewable energy systems, such as electrochemical water splitting and rechargeable metal–air batteries. In this regard, ongoing efforts have been devoted to seeking high-performance electrocatalysts for enhanced energy conversion efficiency. Apart from traditional precious-metal-based catalysts, nickel-based compounds are the most promising earth-abundant OER catalysts, attracting ever-increasing interest due to high activity and stability. In this review, the recent progress on nickel-based oxide and (oxy)hydroxide composites for water oxidation catalysis in terms of materials design/synthesis and electrochemical performance is summarized. Some underlying mechanisms to profoundly understand the catalytic active sites are also highlighted. In addition, the future research trends and perspectives on the development of Ni-based OER electrocatalysts are discussed. 相似文献
38.
39.
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
40.
Huang Huaijing Wu Zhaoqi Zhu Chuanxi Fei Shao-Ming 《International Journal of Theoretical Physics》2021,60(7):2368-2379
International Journal of Theoretical Physics - Quantifying the quantumness of ensembles is a vital and practical task in quantum information theory. In this paper, we quantify the quantumness of... 相似文献