全文获取类型
收费全文 | 504篇 |
免费 | 12篇 |
国内免费 | 7篇 |
专业分类
化学 | 346篇 |
晶体学 | 3篇 |
力学 | 18篇 |
数学 | 48篇 |
物理学 | 108篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 15篇 |
2021年 | 18篇 |
2020年 | 19篇 |
2019年 | 19篇 |
2018年 | 13篇 |
2017年 | 13篇 |
2016年 | 18篇 |
2015年 | 7篇 |
2014年 | 19篇 |
2013年 | 29篇 |
2012年 | 43篇 |
2011年 | 38篇 |
2010年 | 26篇 |
2009年 | 25篇 |
2008年 | 46篇 |
2007年 | 34篇 |
2006年 | 21篇 |
2005年 | 27篇 |
2004年 | 22篇 |
2003年 | 4篇 |
2002年 | 12篇 |
2001年 | 5篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1948年 | 3篇 |
排序方式: 共有523条查询结果,搜索用时 0 毫秒
511.
We consider an S=1 Heisenberg chain with strong exchange (Delta=J(z)/J(perpendicular)) and single-ion uniaxial anisotropy (D) in a magnetic field (B) along the symmetry axis. The low-energy spectrum is described by an effective S=1/2 XXZ model that acts on two different low-energy sectors for a finite range of fields. The vacuum of each sector exhibits Ising-like antiferromagnetic ordering coexisting with the finite spin stiffness obtained from the exact solution of the XXZ model. In this way, we demonstrate the existence of a spin supersolid phase. We also compute the full Delta-B quantum phase diagram using a quantum Monte Carlo method. 相似文献
512.
We derive an effective Hamiltonian H(eff) for an ionic Hubbard chain, valid for tt) and the Mott insulator (MI) (U-Delta>t). Using spin-particle transformations [Phys. Rev. Lett. 86, 1082 (2001)]], we map H(eff)(U=Delta) into an SU(3) antiferromagnetic Heisenberg model whose exact ground state is known. In this way, we show rigorously that a spontaneously dimerized insulating ferroelectric phase appears in the transition region between the BI and the MI. 相似文献
513.
MM Altarawneh GW Chern N Harrison CD Batista A Uchida M Jaime DG Rickel SA Crooker CH Mielke JB Betts JF Mitchell MJ Hoch 《Physical review letters》2012,109(3):037201
We present magnetization and magnetostriction studies of LaCoO_{3} in magnetic fields approaching 100?T. In contrast with expectations from single-ion models, the data reveal two distinct first-order transitions and well-defined magnetization plateaus. The magnetization at the higher plateau is only about half the saturation value expected for spin-1 Co^{3+} ions. These findings strongly suggest collective behavior induced by interactions between different electronic configurations of Co^{3+} ions. We propose a model that predicts crystalline spin textures and a cascade of four magnetic phase transitions at high fields, of which the first two account for the experimental data. 相似文献
514.
Ana Silva Beatriz Antunes Alberta Batista Filipa Pinto-Ribeiro Ftima Baltazar Julieta Afonso 《Molecules (Basel, Switzerland)》2022,27(1)
Proliferating cancer cells have high energy demands, which is mainly obtained through glycolysis. The transmembrane trafficking of lactate, a major metabolite produced by glycolytic cancer cells, relies on monocarboxylate transporters (MCTs). MCT1 optimally imports lactate, although it can work bidirectionally, and its activity has been linked to cancer aggressiveness and poor outcomes. AZD3965, a specific MCT1 inhibitor, was tested both in vitro and in vivo, with encouraging results; a phase I clinical trial has already been undertaken. Thus, analysis of the experimental evidence using AZD3965 in different cancer types could give valuable information for its clinical use. This systematic review aimed to assess the in vivo anticancer activity of AZD3965 either alone (monotherapy) or with other interventions (combination therapy). Study search was performed in nine different databases using the keywords “AZD3965 in vivo” as search terms. The results show that AZD3965 successfully decreased tumor growth and promoted intracellular lactate accumulation, which confirmed its effectiveness, especially in combined therapy. These results support the setup of clinical trials, but other important findings, namely AZD3965 enhanced activity when given in combination with other therapies, or MCT4-induced treatment resistance, should be further considered in the clinical trial design to improve therapy response. 相似文献
515.
We present a new approach to study the thermodynamic properties of d-dimensional classical systems by reducing the problem to the computation of ground state properties of a d-dimensional quantum model. This classical-to-quantum mapping allows us to extend the scope of standard optimization methods by unifying them under a general framework. The quantum annealing method is naturally extended to simulate classical systems at finite temperatures. We derive the rates to assure convergence to the optimal thermodynamic state using the adiabatic theorem of quantum mechanics. For simulated and quantum annealing, we obtain the asymptotic rates of T(t) approximately (pN)/(k(B)logt) and gamma(t) approximately (Nt)(-c/N), for the temperature and magnetic field, respectively. Other annealing strategies are also discussed. 相似文献
516.
517.
Monatshefte für Mathematik - The aim of this paper is to study compact Riemannian manifolds $$(M,,g)$$ that admit a non-constant solution to the system of equations $$begin{aligned} -Delta... 相似文献
518.
Coelho Dyovani Cuadros Linares Oscar A. Oliveira Aloadir L. S. Andrade Jr Marcos A. S. Mascaro Lucia H. Batista Neto João E. S. Bruno Odemir M. Pereira Ernesto C. 《Journal of Solid State Electrochemistry》2020,24(8):1909-1919
Journal of Solid State Electrochemistry - Herein, we propose an approach to three-dimensional (3D) reconstruction of corroded samples to have access to information about the shape, diameter,... 相似文献
519.
520.
Wagner Batista dos Santos Kelly Aparecida Encarnao Amorim Anderson Dourado Galvo Fabricio Tarso Moraes Dario Batista Fortaleza Luiz Alfredo Pavanin 《Photochemistry and photobiology》2019,95(6):1306-1310
Photochemical reactions of ruthenium (II) complexes of type trans‐[Ru(NH3)4LL']2+, where L is a nitrogenous heterocyclic ligand, pyridine (py), isonicotinamide (isn), 4‐acetylpyridine (4‐acpy) or 4‐picoline (4‐pic), and L´ is a 1,2‐bis(4‐pyridyl)ethane (bpa) ligand, were studied with the purpose of evaluating the ligand exchange when, in solution, the complexes are irradiated at the wavelengths of 365, 436, 480 and 519 nm. The study revealed that at lower wavelengths, a labilization process is observed for py and 4‐pic ligands, even at low quantum yields, indicating the dependence of the photolabeling process on the wavelength. The study also reveals that for the filters of greater wavelength, the processes of photolabilization do not occur for any of the studied complexes. The study also shows that there are no photolization processes for the complexes obtained with the isn and 4‐acpy ligands, and it is therefore possible to classify them as nonreactive. 相似文献