全文获取类型
收费全文 | 112711篇 |
免费 | 6709篇 |
国内免费 | 5003篇 |
专业分类
化学 | 49124篇 |
晶体学 | 1161篇 |
力学 | 9209篇 |
综合类 | 347篇 |
数学 | 35698篇 |
物理学 | 28884篇 |
出版年
2024年 | 70篇 |
2023年 | 723篇 |
2022年 | 803篇 |
2021年 | 1183篇 |
2020年 | 1498篇 |
2019年 | 1385篇 |
2018年 | 11342篇 |
2017年 | 11029篇 |
2016年 | 7584篇 |
2015年 | 2496篇 |
2014年 | 2306篇 |
2013年 | 2904篇 |
2012年 | 6965篇 |
2011年 | 13783篇 |
2010年 | 7780篇 |
2009年 | 8068篇 |
2008年 | 8811篇 |
2007年 | 10718篇 |
2006年 | 2324篇 |
2005年 | 3030篇 |
2004年 | 2965篇 |
2003年 | 3086篇 |
2002年 | 2102篇 |
2001年 | 1194篇 |
2000年 | 1117篇 |
1999年 | 1010篇 |
1998年 | 868篇 |
1997年 | 745篇 |
1996年 | 838篇 |
1995年 | 703篇 |
1994年 | 624篇 |
1993年 | 513篇 |
1992年 | 474篇 |
1991年 | 418篇 |
1990年 | 353篇 |
1989年 | 315篇 |
1988年 | 255篇 |
1987年 | 212篇 |
1986年 | 188篇 |
1985年 | 162篇 |
1984年 | 115篇 |
1983年 | 106篇 |
1982年 | 89篇 |
1981年 | 78篇 |
1980年 | 68篇 |
1979年 | 54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 46 毫秒
31.
S. Q. Hou W. Wang Z. Y. Wang Z. W. Hu K. Liu 《Journal of Applied Mechanics and Technical Physics》2018,59(1):153-162
In order to investigate the characteristics of force chains in a granular flow system, a parallel plate shear cell is constructed to simulate the shear movement of an infinite parallel plate and observe variations in relevant parameters. The shear dilatancy process is divided into three stages, namely, plastic strain, macroscopic failure, and granular recombination. The stickslip phenomenon is highly connected with the evolution of force chains during the shear dilatancy process. The load–distribution rate curves and patterns of the force chains are utilized to describe the load-carrying behaviors and morphologic changes of force chains separately. Force chains, namely, “diagonal gridding,” “tadpole-shaped,” and “pinnate” are defined according to the form of the force chains in the corresponding three stages. 相似文献
32.
Lithium-sulfur batteries (LSBs) with high energy density and low cost have been recognized as one of the most promising next-generation energy storage systems. Although it has taken decades of development, the practical application of LSBs has been hindered by several inherent obstacles, particularly the severe shuttle effect and sluggish reaction kinetics in the sulfur cathode. Various strategies have been proposed to address these problems via rational design of electrode materials and configurations. Freestanding sulfur cathode could be a promising strategy to improve the sulfur mass loading at the cathode level and energy density of LSBs. This minireview will briefly summary the recent advances in freestanding cathodes for LSBs. The advantages and disadvantages of various freestanding cathodes are discussed and the prospects for the development of flexible cathodes are envisioned. 相似文献
33.
Simultaneous quantitative determination of 20 active components in the traditional Chinese medicine formula Zhi‐Zi‐Da‐Huang decoction by liquid chromatography coupled with mass spectrometry: application to study the chemical composition variations in different combinations 下载免费PDF全文
Zheng Tang Ran Yin Kaishun Bi Heyun Zhu Fei Han Kelin Chen Fenrong Wang 《Biomedical chromatography : BMC》2015,29(9):1406-1414
34.
35.
Si-Yang Feng Tao Zheng Ai-Jing Sun Zuo-Xiang Wang 《Molecular Crystals and Liquid Crystals》2019,692(1):43-52
AbstractComplexes of [CdL2(NO3)2]·1.5H2O and [Ag2(μ-L)2(NO3)2] were synthesized by the reactions of 2-p-methylphenyl-5-(2-pyridyl)-1,3,4-thiadiazole (L) with Cd(NO3)2·4H2O and AgNO3, respectively. Their structures were determined by single crystal X-ray diffraction. The photophysical property and thermal stability were characterized by FT???IR, UV???Vis absorption, fluorescence, and thermogravimetric analysis (TGA). Both complexes belong to the triclinic system with space group p???1. The central metal of [CdL2(NO3)2]·1.5H2O has a distorted octahedral geometry [CdN4O2], while two central Ag(I) atoms of [Ag2(μ-L)2(NO3)2] exhibit distorted tetrahedral geometries [AgN3O]. 相似文献
36.
Zhang Jia-Rui Zhang Jia-Qi Zheng Zhao-Lin Lin Da Shen Yu-Jia 《Nonlinear dynamics》2022,108(2):1005-1026
Nonlinear Dynamics - Parametrically excited oscillators are used in several domains, in particular to improve the dynamical behaviour of systems like in the case of the parametric amplification or... 相似文献
37.
38.
39.
40.
Ionics - This study aims to explore the potential merits of palladium oxide sensing electrode. PdO is applied on a solid-state potentiometric sensor on an yttria-stabilized zirconia (YSZ)... 相似文献