全文获取类型
收费全文 | 12255篇 |
免费 | 2044篇 |
国内免费 | 1738篇 |
专业分类
化学 | 8986篇 |
晶体学 | 151篇 |
力学 | 736篇 |
综合类 | 127篇 |
数学 | 1596篇 |
物理学 | 4441篇 |
出版年
2024年 | 12篇 |
2023年 | 173篇 |
2022年 | 262篇 |
2021年 | 350篇 |
2020年 | 427篇 |
2019年 | 442篇 |
2018年 | 390篇 |
2017年 | 380篇 |
2016年 | 543篇 |
2015年 | 567篇 |
2014年 | 710篇 |
2013年 | 895篇 |
2012年 | 1065篇 |
2011年 | 1213篇 |
2010年 | 873篇 |
2009年 | 892篇 |
2008年 | 1010篇 |
2007年 | 868篇 |
2006年 | 793篇 |
2005年 | 605篇 |
2004年 | 456篇 |
2003年 | 361篇 |
2002年 | 382篇 |
2001年 | 336篇 |
2000年 | 301篇 |
1999年 | 253篇 |
1998年 | 194篇 |
1997年 | 170篇 |
1996年 | 196篇 |
1995年 | 170篇 |
1994年 | 107篇 |
1993年 | 104篇 |
1992年 | 86篇 |
1991年 | 84篇 |
1990年 | 65篇 |
1989年 | 65篇 |
1988年 | 39篇 |
1987年 | 38篇 |
1986年 | 34篇 |
1985年 | 25篇 |
1984年 | 19篇 |
1983年 | 21篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1974年 | 4篇 |
1972年 | 4篇 |
1971年 | 3篇 |
1957年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
51.
Mei-Feng Dai Ting-Ting Ju Yong-Bo Hou Fang Huang Dong-Lei Tang Wei-Yi Su 《理论物理通讯》2020,72(5):55602-112
The weighted self-similar network is introduced in an iterative way. In order to understand the topological properties of the self-similar network, we have done a lot of research in this field.Firstly, according to the symmetry feature of the self-similar network, we deduce the recursive relationship of its eigenvalues at two successive generations of the transition-weighted matrix.Then, we obtain eigenvalues of the Laplacian matrix from these two successive generations.Finally, we calculate an accurate expression for the eigentime identity and Kirchhoff index from the spectrum of the Laplacian matrix. 相似文献
52.
本文从理论上研究了在双色频率梳激光场驱动下多光子谐波辐射光谱中的相位突变现象。我们利用Floquet理论非微扰地模拟了频率梳激光场与原子分子等量子系统的相互作用过程。谐波辐射信号是多光子偶极跃迁相干叠加的结果,通过调节频率梳激光场间的相对相位,可以相干地控制谐波辐射信号的强度。通过对谐波信号进行傅里叶变换,可以提取不同跃迁路径的相对相位信息。我们通过改变频率梳组激光场的强度和频率组分实现多光子跃迁频率,让其跨越共振跃迁频率时,谐波相位会发生突变。从而可以观测超强激光场驱动下量子系统共振跃迁频率的斯塔克能移。 相似文献
53.
设计了一种宽带的基于混合表面等离子体弯曲波导的偏振分束转换器, 使用有限元法计算硅波导、混合表面等离子体波导的模场分布和有效折射率, 为器件建模仿真分析提供了依据. 使用时域有限差分法优化器件结构, 以获得最佳的性能参数. 由于混合表面等离子体波导的双折射增强, 设计获得的偏振分束转换器具有超小尺寸和宽带的工作特性. 仿真结果表明 在1550nm的中心波长处消光比大于23dB, 插入损耗小于0.8dB; 在80nm的带宽上, 横磁偏振光转换为横电偏振光的偏振转换效率大于95%. 相似文献
54.
Nonlinear Dynamics - We develop a new cross-sample entropy, namely the multiscale cross-trend sample entropy (MCTSE), to investigate the synchronism of dynamical structure regarding two series with... 相似文献
55.
In this paper we report the desgin and synthesis of dihydroxyindoles oligomers based reversible fluorescence sensor.We find dihydroxyindoles-2-carboxylic acid derived oligmer(P-DHICA)has the highest selectivity and sensitivity for Cu^2+detection.This work provide a highly efficient,environmentally friendly biosensor for potential use in medical testing. 相似文献
56.
Tong Liu Zhen-Fei Zheng Yu Zhang Yu-Liang Fang Chui-Ping Yang 《Frontiers of Physics》2020,15(2):21603-37
We propose a method for transferring quantum entangled states of two photonic cat-state qubits(cqubits)from two microwave cavities to the other two microwave cavities.This proposal is realized by using four microwave cavities coupled to a superconducting flux qutrit.Because of using four cavities with different frequencies,the inter-cavity crosstalk is significantly reduced.Since only one coupler qutrit is used,the circuit resource is minimized.The entanglement transfer is completed with a singlestep operation only,thus this proposal is quite simple.The third energy level of the coupler qutrit is not populated during the state transfer,therefore decoherence from the higher energy level is greatly suppressed.Our numerical simulations show that high-fidelity transfer of two-cqubit entangled states from two transmission line resonators to the other two transmission line resonators is feasible with current circuit QED technology.This proposal is universal and can be applied to accomplish the same task in a wide range of physical systems,such as four microwave or optical cavities,which are coupled to a natural or artificial three-level atom. 相似文献
57.
Gzal M. Fang B. Vakakis A. F. Bergman L. A. Gendelman O. V. 《Nonlinear dynamics》2020,101(4):2087-2106
Nonlinear Dynamics - This paper describes a rapid and efficient nonlinear non-resonance mechanism for low-to-high-frequency energy scattering, which is referred to as intermodal targeted energy... 相似文献
58.
QiuHong Wang Abdusalam Abdukerim Wei Chen Xun Chen YunHua Chen XiangYi Cui YingJie Fan DeQing Fang ChangBo Fu LiSheng Geng Karl Giboni Franco Giuliani LinHui Gu XuYuan Guo Ke Han ChangDa He Di Huang Yan Huang YanLin Huang Zhou Huang Peng Ji XiangDong Ji YongLin Ju YiHui Lai Kun Liang HuaXuan Liu JiangLai Liu WenBo Ma YuGang Ma YaJun Mao Yue Meng Parinya Namwongsa KaiXiang Ni JinHua Ning XuYang Ning XiangXiang Ren ChangSong Shang Lin Si AnDi Tan AnQing Wang HongWei Wang Meng Wang SiGuang Wang XiuLi Wang Zhou Wang MengMeng Wu ShiYong Wu JingKai Xia MengJiao Xiao PengWei Xie BinBin Yan JiJun Yang Yong Yang ChunXu Yu Jumin Yuan Dan Zhang HongGuang Zhang Tao Zhang Li Zhao QiBin Zheng JiFang Zhou Ning Zhou XiaoPeng Zhou 《中国科学:物理学 力学 天文学(英文版)》2020,(3):54-63
In dark matter direct detection experiments,neutron is a serious source of background,which can mimic the dark matter-nucleus scattering signals.In this paper,we present an improved evaluation of the neutron background in the PandaX-II dark matter experiment by a novel approach.Instead of fully relying on the Monte Carlo simulation,the overall neutron background is determined from the neutron-induced high energy signals in the data.In addition,the probability of producing a dark-matter-like background per neutron is evaluated with a complete Monte Carlo generator,where the correlated emission of neutron(s)andγ(s)in the(α,n)reactions and spontaneous fissions is taken into consideration.With this method,the neutron backgrounds in the Run 9(26-ton-day)and Run 10(28-ton-day)data sets of PandaX-II are estimated to be(0.66±0.24)and(0.47±0.25)events,respectively. 相似文献
59.
Yueyue Li Yanan Ban Ruihui Wang Zheng Wang Zhanxian Li Chenjie Fang Mingming Yu 《中国化学快报》2020,31(2):443-446
A ratiometric fluorescent hybrid nanoprobe CDs-1 for arginine(Arg),exhibiting high sensitivity(the limit of detection,LOD,being 6.5×10^-8 mol/L) and excellent selectivity and anti-interference ability,was fabricated through fluorescence resonance energy transfer(FRET) and the electrostatic attraction between positively-charged hemicyanine molecules and negatively-charged carbon dots(CDs).Arg can be quantitatively detected in the concentration range from 6.0×10^-5 mol/L to 2.7×10^-4 mol/L.Further,due to its ability to target mitochondrion and low cytotoxicity,intracellular Arg was succes s fully tracked through ratiometric fluorescence imaging. 相似文献
60.
Huadong Yuan Prof. Jianwei Nai Dr. Yongjin Fang Gongxun Lu Prof. Xinyong Tao Prof. Xiong Wen Lou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(37):15973-15977
The growth of Li dendrites hinders the practical application of lithium metal anodes (LMAs). In this work, a hollow nanostructure, based on hierarchical MoS2 coated hollow carbon particles preloaded with sulfur (C@MoS2/S), was designed to modify the LMA. The C@MoS2 hollow nanostructures serve as a good scaffold for repeated Li plating/stripping. More importantly, the encapsulated sulfur could gradually release lithium polysulfides during the Li plating/stripping, acting as an effective additive to promote the formation of a mosaic solid electrolyte interphase layer embedded with crystalline hybrid lithium-based components. These two factors together effectively suppress the growth of Li dendrites. The as-modified LMA shows a high Coulombic efficiency of 98 % over 500 cycles at the current density of 1 mA cm−2. When matched with a LiFePO4 cathode, the assembled full cell displays a highly improved cycle life of 300 cycles, implying the feasibility of the proposed LMA. 相似文献