全文获取类型
收费全文 | 27642篇 |
免费 | 3618篇 |
国内免费 | 3578篇 |
专业分类
化学 | 9585篇 |
晶体学 | 189篇 |
力学 | 3719篇 |
综合类 | 250篇 |
数学 | 8948篇 |
物理学 | 12147篇 |
出版年
2024年 | 68篇 |
2023年 | 299篇 |
2022年 | 488篇 |
2021年 | 686篇 |
2020年 | 896篇 |
2019年 | 813篇 |
2018年 | 812篇 |
2017年 | 981篇 |
2016年 | 1158篇 |
2015年 | 1025篇 |
2014年 | 1453篇 |
2013年 | 2389篇 |
2012年 | 1563篇 |
2011年 | 1840篇 |
2010年 | 1465篇 |
2009年 | 1863篇 |
2008年 | 1900篇 |
2007年 | 1968篇 |
2006年 | 1648篇 |
2005年 | 1443篇 |
2004年 | 1187篇 |
2003年 | 1206篇 |
2002年 | 1015篇 |
2001年 | 801篇 |
2000年 | 782篇 |
1999年 | 666篇 |
1998年 | 589篇 |
1997年 | 467篇 |
1996年 | 350篇 |
1995年 | 318篇 |
1994年 | 281篇 |
1993年 | 252篇 |
1992年 | 233篇 |
1991年 | 202篇 |
1990年 | 205篇 |
1989年 | 180篇 |
1988年 | 159篇 |
1987年 | 155篇 |
1986年 | 111篇 |
1985年 | 126篇 |
1984年 | 115篇 |
1983年 | 41篇 |
1982年 | 82篇 |
1981年 | 78篇 |
1980年 | 62篇 |
1979年 | 71篇 |
1978年 | 66篇 |
1977年 | 71篇 |
1976年 | 64篇 |
1973年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
《Indagationes Mathematicae》2022,33(1):218-237
We define the notion of basic set data for finite groups (building on the notion of basic set, but including an order on the irreducible characters as part of the structure), and we prove that the Springer correspondence provides basic set data for Weyl groups. Then we use this to determine explicitly the modular Springer correspondence for classical types (defined over a base field of odd characteristic , and with coefficients in a field of odd characteristic ): the modular case is obtained as a restriction of the ordinary case to a basic set. In order to do so, we compare the order on bipartitions introduced by Dipper and James with the order induced by the Springer correspondence. We provide a quick proof, by sorting characters according to the dimension of the corresponding Springer fibre, an invariant which is directly computable from symbols. 相似文献
23.
The magnetic skyrmion transport driven by pure voltage-induced strain gradient is proposed and studied via micromagnetic simulation. Through combining the skyrmion with multiferroic heterojunction, a voltage-induced uniaxial strain gradient is adjusted to move skyrmions. In the system, a pair of short-circuited trapezoidal top electrodes can generate the symmetric strain. Due to the symmetry of strain, the magnetic skyrmion can be driven with a linear motion in the middle of the nanostrip without deviation. We calculate the strain distribution generated by the trapezoidal top electrodes pair, and further investigate the influence of the strain intensity as well as the strain gradient on the skyrmion velocity. Our findings provide a stable and low-energy regulation method for skyrmion transport. 相似文献
24.
25.
Two-dimensional van der Waals magnetic materials are intriguing for applications in the future spintronics devices, so it is crucial to explore strategy to control the magnetic properties. Here, we carried out first-principles calculations and Monte Carlo simulations to investigate the effect of biaxial strain and hydrostatic pressure on the magnetic properties of the bilayer CrI3. We found that the magnetic anisotropy, intralayer and interlayer exchange interactions, and Curie temperature can be tuned by biaxial strain and hydrostatic pressure. Large compressive biaxial strain may induce a ferromagneticto-antiferromagnetic transition of both CrI3 layers. The hydrostatic pressure could enhance the intralayer exchange interaction significantly and hence largely boost the Curie temperature. The effect of the biaxial strain and hydrostatic pressure revealed in the bilayer CrI3 may be generalized to other two-dimensional magnetic materials. 相似文献
26.
通过对比分析传染病传染机制与隐性知识的转移过程,引入SIR模型,根据隐性知识转移的特点对SIR模型进行改进,并在组织遗忘视角下,将员工知识遗忘细分为主动遗忘和被动遗忘,建立知识密集型企业隐性知识转移模型.而后,通过Matlab对该模型的演化函数进行模拟,分析知识接收方占比、知识转移能力、知识遗忘率及核心员工流失率对知识密集型企业隐性知识转移的影响.最后,基于模拟分析结果,为提升知识密集型企业隐性知识转移效益提出相应策略. 相似文献
27.
28.
Dr. Qing Tang 《Chemphyschem》2019,20(4):595-601
Among the widely studied 2D transition metal dichalcogenides (TMDs), MoTe2 has attracted special interest for phase-change applications due to its small 2H-1T′ energy difference, yet a large scale phase transition without structural disruption remains a significant challenge. Recently, an interesting long-range phase engineering of MoTe2 has been realized experimentally by Ca2N electride. However, the interface formed between them has not been well understood, and moreover, it remains elusive how the presence of Ca2N would affect the basal plane reactivity of MoTe2. To address this, we performed density functional theory (DFT) calculations to investigate the potential of tuning the phase stability and chemical reactivity of a MoTe2 monolayer via interacting with Ca2N to form a van der Walls heterostructure. We found that the contact nature at the 2H-MoTe2/Ca2N interface is Schottky-barrier-free, allowing for the spontaneous electron transfer from Ca2N to 2H-MoTe2 to make it strongly n-type doped. Moreover, Ca2N doping significantly lowers the energy of 1T′-MoTe2 and dynamically triggers the 2H-to-1T′ transformation. The Ca2N-induced phase modulation can also be applied to tune the phase energetics of MoS2 and MoSe2. Furthermore, using H adsorption as the testing ground, we also find that the H binding on the basal plane of MoTe2 is enhanced after forming heterostructure with Ca2N, potentially providing basis for surface modification and other related catalytic applications. 相似文献
29.
The first-principles DFT calculations together with microkinetic analysis reveal the complex catalytic mechanism of low-content NO oxidation on CrO2(110) at room temperature. It quantitatively makes clear that CrO2(110) can exhibit considerable activity with the Mars-van-Krevelen mechanism preferred, and the nitrate species serves as the key poisoning species. 相似文献
30.