全文获取类型
收费全文 | 85篇 |
免费 | 114篇 |
国内免费 | 64篇 |
专业分类
化学 | 95篇 |
晶体学 | 1篇 |
力学 | 1篇 |
综合类 | 1篇 |
数学 | 3篇 |
物理学 | 162篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 8篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 11篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 18篇 |
2012年 | 23篇 |
2011年 | 22篇 |
2010年 | 13篇 |
2009年 | 21篇 |
2008年 | 21篇 |
2007年 | 26篇 |
2006年 | 10篇 |
2005年 | 18篇 |
2004年 | 10篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有263条查询结果,搜索用时 31 毫秒
71.
An amperometric horseradish peroxidase inhibition biosensor for the determination of phenylhydrazine
An amperometric horseradish peroxidase (HRP) inhibition biosensor has been substantially constructed by the help of N,N-dicyclohexylcarbodiimide (DCC), N-hydroxysuccinimide (NHS). The preparation steps and the biosensor response to phenylhydrazine were monitored by electrochemical impedance spectroscopy (EIS), cyclic voltammetry, and chronoamperometry. The proposed biosensor could be applied to determine phenylhydrazine in a 0.10 M phosphate buffer solution containing 1.2 mM hydroquinone and 0.50 mM H(2)O(2) by phenylhydrazine, inhibiting the catalytic activity of the HRP enzyme in the reduction of H(2)O(2). The system was optimized to realize a reliable determination of phenylhydrazine in the range of 2.5 x 10(-7) to 1.1 x 10(-6) M with a detection limit of 8.2 x 10(-8) M and a correlation coefficient of 0.999. The modified electrode displayed good reproducibility, sensitivity and stability for the determination of phenylhydrazine. 相似文献
72.
文章报道了激光诱导太赫兹表面等离子谐振效应。采用激光抽运-太赫兹波探测技术,实时改变单晶硅中的载流子浓度,使其介电特性从类绝缘体演变为类金属导体,以支持表面等离子谐振效应,进而实现太赫兹波在周期性亚波长单晶硅孔阵列中的实时可控制谐振增强传输。同时还通过实验观测到太赫兹波从光子晶体效应到表面等离子波的实时演变。文章作者采用Fano模型对实验结果进行模拟分析,获得了与实验数据一致的理论拟合。 相似文献
73.
Staring from a discrete matrix spectral problem, a hierarchy of lattice soliton equations is presented though discrete zero curvature representation. The resulting lattice soliton equations possess non-local Lax pairs. The Hamiltonian structures are established for the resulting hierarchy by the discrete trace identity. Liouville integrability of resulting hierarchy is demonstrated. 相似文献
74.
75.
Spin-Polarized Transport through the T-Shaped Double Quantum Dots with Fano-Kondo Interaction 下载免费PDF全文
We theoretically investigate the spin-polarized transport properties of the T-shaped double quantum dots coupled to two ferromagnetic leads by the Anderson Hamiltonian. The Hamiltonian is solved by means of the slave-boson mean-field theory. We calculate the density of states and the liner conductance in this system with both parallel and antiparallel lead-polarization alignments, and our results show that the transport properties of this system depend on both the tunnelling strength between the two dots and the spin-polarized strength p. This system is a possible candidate for spin valve transistors in the spintronics. 相似文献
76.
A Monte Carlo Study of the Fractal Property inside Jets Produced in High Energy e+e- Collisions 下载免费PDF全文
The anomalous scaling property inside jets produced in e+e- Collisions at s91.2GeV is studied using Monte Carlo method. A new variable r is applied, which has very good anomalous scaling property. The relation between the scaling indices of different orders is investigated. The Lévy index for the hadronic system inside jets is obtained, which turns out to be μ=2.498±0.025, very close to the same index of hadron-hadron collisions. On the contrary, the Lévy index of e+e- collisions is 1.701±0.043, being less than 2. Since the multi-hadron production in e+e- collisions is dominated by hard gluon emission or hard parton branching, while the parton fragmentation into jet, like the multi-production in hadron-hadron collisions, is a soft process, the above results suggest that the value of Lévy index may provide another signal for the qualitative difference between hard and soft processes. 相似文献
77.
We have investigated the persistent current in a mesoscopic ring with a side-coupled quantum dot. The problems are probed by using the one-impurity Anderson Hamiltonian and are treated with the slave boson mean field theory. It is shown that the persistent current in this system has the spin fluctuations, and the charge transfers between the two subsystems are suppressed in the limit of Δ/T_K^0《1. The minimum value of the persistent current for ξ_K/L=5 of the odd parity system provides an opportunity to detect the Kondo screening cloud. 相似文献
78.
In order to study the collisional quantum interference (CQI) on rotational energy transfer in atom-diatom system, we have studied the relation of the integral interference angle and differential interference angle in Na+Na2 (A1Σ+u, v=8∽b3Π0u, v=14) collision system. In this paper, based on the first-Born approximation of time-dependent perturbation theory and takinginto accounts the anisotropic effect of Lennard-Jones interaction potentials,we present a theoretical model of collisional quantum interference inintramolecular rotational energy transfer, and a relationship betweendifferential and integral interference angles. 相似文献
79.
Radio-Frequency Performance of Epitaxial Graphene Field-Effect Transistors on Sapphire Substrates 下载免费PDF全文
We report dc and the first-ever measured small signal rf performance of epitaxial graphene field-effect transistors (GFETs), where the epitaxial graphene is grown by chemical vapor deposition (CVD) on a 2-inch c-plane sapphire substrate. Our epitaxial graphene material has a good flatness and uniformity due to the low carbon concentration during the graphene growth. With a gate length Lg = 100 nm, the maximum drain source current Ids and peak transconductance gm reach 0.92 A/mm and 0.143 S/mm, respectively, which are the highest results reported for GFETs directly grown on sapphire. The extrinsic cutoff frequency (fT) and maximum oscillation frequency (fmax) of the device are 12 GHz and 9.5 GHz, and up to 32 GHz and 21.5 GHz after de-embedding, respectively. Our work proves that epitaxial graphene on sapphire substrates is a promising candidate for rf electronics. 相似文献
80.