全文获取类型
收费全文 | 12593篇 |
免费 | 588篇 |
国内免费 | 150篇 |
专业分类
化学 | 8959篇 |
晶体学 | 104篇 |
力学 | 591篇 |
综合类 | 4篇 |
数学 | 1615篇 |
物理学 | 2058篇 |
出版年
2024年 | 37篇 |
2023年 | 122篇 |
2022年 | 691篇 |
2021年 | 578篇 |
2020年 | 454篇 |
2019年 | 525篇 |
2018年 | 532篇 |
2017年 | 441篇 |
2016年 | 722篇 |
2015年 | 485篇 |
2014年 | 642篇 |
2013年 | 1247篇 |
2012年 | 936篇 |
2011年 | 914篇 |
2010年 | 638篇 |
2009年 | 519篇 |
2008年 | 590篇 |
2007年 | 528篇 |
2006年 | 382篇 |
2005年 | 391篇 |
2004年 | 250篇 |
2003年 | 251篇 |
2002年 | 200篇 |
2001年 | 108篇 |
2000年 | 69篇 |
1999年 | 84篇 |
1998年 | 50篇 |
1997年 | 58篇 |
1996年 | 65篇 |
1995年 | 41篇 |
1994年 | 47篇 |
1993年 | 33篇 |
1992年 | 52篇 |
1991年 | 43篇 |
1990年 | 38篇 |
1989年 | 38篇 |
1988年 | 37篇 |
1987年 | 37篇 |
1986年 | 38篇 |
1985年 | 46篇 |
1984年 | 41篇 |
1983年 | 30篇 |
1982年 | 38篇 |
1981年 | 20篇 |
1980年 | 33篇 |
1979年 | 29篇 |
1978年 | 26篇 |
1976年 | 19篇 |
1975年 | 17篇 |
1974年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
Kacimi Rachid Bourass Mohamed Toupance Thierry Wazzan Nuha Chemek Mourad El Alamy Aziz Bejjit Lahcen Alimi Kamel Bouachrine Mohammed 《Research on Chemical Intermediates》2020,46(6):3247-3262
Research on Chemical Intermediates - A theoretical study on four organic dyes based on bis(4-hexyloxy)triphenylamine as donor and electron acceptor cyanoacrylic acid with a... 相似文献
12.
In this paper, the deformation of the Heisenberg algebra, consistent with both the generalized uncertainty principle and doubly special relativity, has been analyzed. It has been observed that, though this algebra can give rise to fractional derivative terms in the corresponding quantum mechanical Hamiltonian, a formal meaning can be given to them by using the theory of harmonic extensions of function. Depending on this argument, the expression of the propagator of the path integral corresponding to the deformed Heisenberg algebra, has been obtained. In particular, the consistent expression of the one dimensional free particle propagator has been evaluated explicitly. With this propagator in hand, it has been shown that, even in free particle case, normal generalized uncertainty principle and doubly special relativity show very much different result. 相似文献
13.
Afzal Asif Mohammed Samee A. D. Abdul Razak R. K. Ramis M. K. 《Journal of Thermal Analysis and Calorimetry》2021,144(4):1271-1285
Journal of Thermal Analysis and Calorimetry - The operating temperature of Li-ion batteries used in modern electric vehicles should be maintained within an allowable range to avoid thermal runaway... 相似文献
14.
15.
Following a thermal reduction method, platinum nanoparticles were synthesized and stabilized by polyvinylpyrrolidone. The colloidal platinum nanoparticles were stable for more than 3 months. The micrograph analysis unveiled that the colloidal platinum nanoparticles were well dispersed with an average size of 2.53 nm. The sol–gel‐based inverse micelle strategy was applied to synthesize mesoporous iron oxide material. The colloidal platinum nanoparticles were deposited on mesoporous iron oxide through the capillary inclusion method. The small‐angle X‐ray scattering analysis indicated that the dimension of platinum nanoparticles deposited on mesoporous iron oxide (Pt‐Fe2O3) was 2.64 nm. X‐ray photoelectron spectroscopy (XPS) data showed that the binding energy on Pt‐Fe2O3 surface decreased owing to mesoporous support–nanoparticle interaction. Both colloidal and deposited platinum nanocatalysts improved the degradation of methyl orange under reduction conditions. The activation energy on the deposited platinum nanocatalyst interface (2.66 kJ mol?1) was significantly lowered compared with the one on the colloidal platinum nanocatalyst interface (40.63 ± 0.53 kJ mol?1). 相似文献
16.
Kai He Tsegaye TadesseTsega Xi Liu Jiantao Zai Xin‐Hao Li Xuejiao Liu Wenhao Li Nazakat Ali Xuefeng Qian 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(34):12029-12035
The modulation of electron density is an effective option for efficient alternative electrocatalysts. Here, p‐n junctions are constructed in 3D free‐standing FeNi‐LDH/CoP/carbon cloth (CC) electrode (LDH=layered double hydroxide). The positively charged FeNi‐LDH in the space‐charge region can significantly boost oxygen evolution reaction. Therefore, the j at 1.485 V (vs. RHE) of FeNi‐LDH/CoP/CC achieves ca. 10‐fold and ca. 100‐fold increases compared to those of FeNi‐LDH/CC and CoP/CC, respectively. Density functional theory calculation reveals OH? has a stronger trend to adsorb on the surface of FeNi‐LDH side in the p‐n junction compared to individual FeNi‐LDH further verifying the synergistic effect in the p‐n junction. Additionally, it represents excellent activity toward water splitting. The utilization of heterojunctions would open up an entirely new possibility to purposefully regulate the electronic structure of active sites and promote their catalytic activities. 相似文献
17.
Nonlinear Dynamics - Introduction of stiffness nonlinearities to broaden the frequency bandwidth of vibratory energy harvesters has the adverse influence of complicating the response behavior of... 相似文献
18.
19.
20.