全文获取类型
收费全文 | 414篇 |
免费 | 19篇 |
国内免费 | 3篇 |
专业分类
化学 | 257篇 |
力学 | 16篇 |
数学 | 41篇 |
物理学 | 122篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 14篇 |
2018年 | 22篇 |
2017年 | 14篇 |
2016年 | 33篇 |
2015年 | 15篇 |
2014年 | 32篇 |
2013年 | 49篇 |
2012年 | 38篇 |
2011年 | 51篇 |
2010年 | 23篇 |
2009年 | 30篇 |
2008年 | 26篇 |
2007年 | 18篇 |
2006年 | 14篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有436条查询结果,搜索用时 421 毫秒
421.
Mohammad Sadegh Sadeghi Zadeh Monireh Houshmand Hossein Aghababa 《International Journal of Theoretical Physics》2017,56(7):2101-2112
In this paper, a new scheme of bidirectional quantum teleportation (BQT) making use of an eight-qubit entangled state as the quantum channel is presented. This scheme is the first protocol without controller by which the users can teleport an arbitrary two-qubit state to each other simultaneously. This protocol is based on the ControlledNOT operation, appropriate single-qubit unitary operations and single-qubit measurement in the Z-basis and X-basis. 相似文献
422.
J. Sadeghi M.R. Setare B. Pourhassan 《The European Physical Journal C - Particles and Fields》2008,53(1):95-97
In this paper we consider the two dimensional black hole and use Wald’s formula to find its entropy. Also we consider higher
derivative terms. We discuss the case of a massless black hole and find its free energy. 相似文献
423.
Research on Chemical Intermediates - In this research, the applicability of NaY/Mn0.5Zn0.5Fe2O4 as a new synthesized nanocomposite adsorbent for the adsorption and degradation of methyl parathion... 相似文献
424.
Fatemeh Vahdati Rad Mohammad Reza Housaindokht Razieh Jalal Hossein Eshtiagh Hosseini Asma Verdian Doghaei Sadegh Sadeghi Goghari 《Journal of fluorescence》2014,24(4):1225-1234
Blocking the division of tumor cells by small-molecules is currently of great interest for the design of new antitumor drugs. The interaction of a new metal complex with DNA was investigated through several techniques. Absorption spectroscopy and gel electrophoresis studies on the interaction of the Cu-complex of (2a-4mpyH)2 [Cu(pyzdc)2 (H2O)2].6 H2O with DNA have shown that this complex can bind to CT-DNA with binding constant 3.99?×?105 M?1. The cyclic voltammetry (CV) responses of the metal complex in the presence of CT-DNA have shown that the metal complex can bind to CT-DNA through partial intercalation mode and this is consistent with molecular docking analysis, quenching process and thermal denaturation experiments. The cytotoxicity of this complex has been evaluated by MTT assay. The results of cell viability assay on DU145 cell line revealed that the metal complex had cytotoxic effects. 相似文献
425.
J. Sadeghi B. Pourhassan M. Khurshudyan H. Farahani 《International Journal of Theoretical Physics》2014,53(3):911-920
In this paper we study modified cosmic Chaplygin cosmology with non-zero cosmological constant in non-flat Universe. By using well-known forms of scale factor we obtain time-dependent dark energy density by numerical analysis of non-linear differential equation and fitting curves. We use observational data to fix solution and discuss about stability of our system. First of all we consider cosmological constant as a constant in Einstein equation, and then study possibility of variable cosmological constant. 相似文献
426.
In present work, using density functional theory and extended restricted orientation model, the one particle density of hard Gaussian overlap fluid near the colloid walls is calculated. The hard needle–wall interaction between molecules and colloids are considered. Using non-linear equation, proposed by Grimson–Rickyazen, the solvation force of hard ellipsoidal molecular fluid with hard Gaussian overlap interaction is calculated. We could not find the exact or simulation results for comparison. The results in the case k = 2.0 are compared with the solvation force of one-dimensional hard rod fluids. The results are corresponded, qualitatively. 相似文献
427.
In this Letter, we study the equation of circular loops with time-dependent tension in the BTZ black hole background. We obtain various cases where cosmic string loops finally collapse to form black holes. Also, we study effect of the BTZ black hole mass and angular momentum on the evolution of cosmic string loops. We find the critical values of initial radii as a limit for the cosmic string loops collapsing to form black holes. 相似文献
428.
Tractor cabin’s passive suspension parameters optimization via experimental and numerical methods 总被引:1,自引:0,他引:1
Reduction of transmitted vibrations of tractor cabin which is caused by road roughness is the major objective of this study; consequently operator health can be achieved. This objective is carried out via experimental measurements and finite element modeling. For this purpose the vertical acceleration of the cabin as well as the rear axle of the tractor is measured in different road conditions and forward speeds. However, it should be mentioned that tests were carried out according to the ISO 2631-1985 but no measurements were done on the driver’s seat. Then the finite element model of the cabin’s tractor is developed and the dynamic response of the cabin interior (with the measured axle acceleration as input dynamic force) is obtained. At the third step the suspension parameters are calculated by comparing the accelerations obtained from the model and measurements. Finally the suspension parameters are optimized according to ISO 2631-1985 via iterative method. 相似文献
429.
Sadeghi H Schulz-Weiling M Morrison JP Yiu JC Saquet N Rennick CJ Grant E 《Physical chemistry chemical physics : PCCP》2011,13(42):18872-18879
Using state-selected double-resonant excitation, we create a Rydberg gas of NO molecules excited to the principal quantum number n = 50 of the f-series converging to the ion rotational level, N(+) = 2. This gas evolves to form an ultracold plasma, which expands under the thermal pressure of its electrons, and dissipates by electron-ion recombination. Under conditions chosen for this experiment, the observed rates of expansion vary with selected plasma density. Electron temperatures derived from these expansion rates vary from T(e) = 12 K for the highest density up to 16 K at four-fold lower density. Over this range, the apparent electron coupling parameter, defined as Γ(e) = e(2)/4πε(0)ak(B)T(e), falls from nearly three to about one. The decay of charged-particle density fits with a kinetic model that includes parallel paths of direct two-body and stepwise three-body dissociative recombination. The overall recombinative decay follows a second-order rate law, with an observed rate constant that fits with established scattering-theory estimates for elementary two-body dissociative recombination. A small residual increase in this rate constant with decreasing charged-particle density suggests a growing importance of the three-body recombination channel under conditions of decreasing electron correlation. 相似文献
430.
J. Sadeghi B. Pourhassan F. Pourasadollah 《The European Physical Journal C - Particles and Fields》2014,74(3):1-8
In this paper, we investigate the dynamics of a heavy quark for plasmas corresponding to three dimensional hairy black holes. We utilize the AdS/CFT correspondence to study the holographic Brownian motion of this particle with different kinds of hairy black holes. For an uncharged black hole in the low frequency limit we derive analytic expressions for the correlation functions and the response functions and verify that the fluctuation–dissipation theorem holds in the presence of a scalar field against a metric background. In the case of a charged black hole, we think that the results are similar to that derived for an uncharged black hole. 相似文献