全文获取类型
收费全文 | 24269篇 |
免费 | 3027篇 |
国内免费 | 2094篇 |
专业分类
化学 | 14632篇 |
晶体学 | 431篇 |
力学 | 1660篇 |
综合类 | 131篇 |
数学 | 2583篇 |
物理学 | 9953篇 |
出版年
2024年 | 46篇 |
2023年 | 380篇 |
2022年 | 604篇 |
2021年 | 695篇 |
2020年 | 812篇 |
2019年 | 855篇 |
2018年 | 763篇 |
2017年 | 696篇 |
2016年 | 973篇 |
2015年 | 976篇 |
2014年 | 1183篇 |
2013年 | 1601篇 |
2012年 | 2039篇 |
2011年 | 2104篇 |
2010年 | 1500篇 |
2009年 | 1577篇 |
2008年 | 1649篇 |
2007年 | 1408篇 |
2006年 | 1365篇 |
2005年 | 1078篇 |
2004年 | 878篇 |
2003年 | 673篇 |
2002年 | 592篇 |
2001年 | 745篇 |
2000年 | 600篇 |
1999年 | 490篇 |
1998年 | 371篇 |
1997年 | 349篇 |
1996年 | 321篇 |
1995年 | 279篇 |
1994年 | 231篇 |
1993年 | 200篇 |
1992年 | 189篇 |
1991年 | 182篇 |
1990年 | 147篇 |
1989年 | 113篇 |
1988年 | 96篇 |
1987年 | 69篇 |
1986年 | 62篇 |
1985年 | 72篇 |
1984年 | 51篇 |
1983年 | 41篇 |
1982年 | 37篇 |
1981年 | 39篇 |
1980年 | 31篇 |
1979年 | 28篇 |
1978年 | 28篇 |
1977年 | 23篇 |
1975年 | 24篇 |
1974年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
11.
12.
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
13.
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
14.
Hierarchical motion planning at the acceleration level based on task priority matrix for space robot
Nonlinear Dynamics - A capacitive micromachined ultrasonic transducer (CMUT) due to many benefits is being considered as an imaging and therapeutic technology recently. The critical challenge is to... 相似文献
15.
Chen Fenge Li Bing Peng Xingchun 《Methodology and Computing in Applied Probability》2022,24(2):635-659
Methodology and Computing in Applied Probability - This paper is devoted to the study of an optimal investment and risk control problem for an insurer. The risky asset process and the insurance... 相似文献
16.
Ding Q. Yao M. Wu Sh. Zeng M. Xue N. Wu D. Xu J. 《Journal of Applied Spectroscopy》2022,89(4):712-718
Journal of Applied Spectroscopy - Based on partial least squares (PLS) analysis, the effects of different smoothing points and different preprocessing methods on the accuracy and precision of the... 相似文献
17.
Transport in Porous Media - The theme of coupling problems for adsorption, absorption and thermochemical transport in porous media is very important for engineering applications. Based on the... 相似文献
18.
19.
Liming Fan Feng Wang Dongsheng Zhao Yuxin Peng Yuxin Deng Yinwei Luo Xiutang Zhang 《应用有机金属化学》2020,34(12):e5960
Guided by the self-penetrating features can improve the stability of metal organic frameworks (MOFs), an unprecedented 3D self-penetrated framework, {[Zn (tptc)0.5(bimb)]·H2O}n ( NUC-6 , here NUC corresponding to North University of China), with 3D (4,4)-c {86} net, was designed. Benefit from the high chemical stability and excellent luminescent property, NUC-6 can be act as an efficient multi-response chemo-sensor in detecting dichloronitroaniline pesticide and nitrofuran antibiotics in water with the detection limits are 116 ppb for DCN pesticide, 16 ppb for NFT antibiotic, and 12 ppb for NTZ antibiotic. Besides, the mechanisms of luminescence quenching were revealed from the viewpoint of internal filter effect (IFE) and photo-induced electron transfer (PET), implied by the optical spectroscopy and quantum chemical calculation. This work provides a promising strategy to design stable MOFs by improving the self-penetrating features and to expand their practical applications in the detection of organic pollutants in aqueous medium. 相似文献
20.
Experimental Mechanics - Insufficient data are available to fully understand the effects of metal additive manufacturing (AM) defects for widespread adoption of the emerging technology.... 相似文献