全文获取类型
收费全文 | 10013篇 |
免费 | 828篇 |
国内免费 | 521篇 |
专业分类
化学 | 1297篇 |
晶体学 | 144篇 |
力学 | 907篇 |
综合类 | 82篇 |
数学 | 7192篇 |
物理学 | 1740篇 |
出版年
2024年 | 14篇 |
2023年 | 82篇 |
2022年 | 106篇 |
2021年 | 123篇 |
2020年 | 264篇 |
2019年 | 265篇 |
2018年 | 264篇 |
2017年 | 274篇 |
2016年 | 293篇 |
2015年 | 239篇 |
2014年 | 439篇 |
2013年 | 949篇 |
2012年 | 374篇 |
2011年 | 576篇 |
2010年 | 578篇 |
2009年 | 655篇 |
2008年 | 705篇 |
2007年 | 643篇 |
2006年 | 555篇 |
2005年 | 504篇 |
2004年 | 428篇 |
2003年 | 386篇 |
2002年 | 346篇 |
2001年 | 271篇 |
2000年 | 222篇 |
1999年 | 223篇 |
1998年 | 174篇 |
1997年 | 165篇 |
1996年 | 149篇 |
1995年 | 129篇 |
1994年 | 108篇 |
1993年 | 84篇 |
1992年 | 75篇 |
1991年 | 55篇 |
1990年 | 49篇 |
1989年 | 36篇 |
1988年 | 43篇 |
1987年 | 26篇 |
1986年 | 46篇 |
1985年 | 48篇 |
1984年 | 56篇 |
1983年 | 42篇 |
1982年 | 52篇 |
1981年 | 43篇 |
1980年 | 42篇 |
1979年 | 48篇 |
1978年 | 32篇 |
1977年 | 18篇 |
1976年 | 20篇 |
1973年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Stability of ion triplets in ionic liquid/lithium salt solutions: Insights from implicit and explicit solvent models and molecular dynamics simulations 下载免费PDF全文
Binding energies of ion triplets formed in ionic liquids by Li+ with two anions have been studied using quantum‐chemical calculations with implicit and explicit solvent supplemented by molecular dynamics (MD) simulations. Explicit solvent approach confirms variation of solute‐ionic liquid interactions at distances up to 2 nm, resulting from structure of solvation shells induced by electric field of the solute. Binding energies computed in explicit solvent and from the polarizable continuum model approach differ largely, even in sign, but relative values generally agree between these two models. Stabilities of ion triplets obtained in quantum‐chemical calculations for some systems disagree with MD results; the discrepancy is attributed to the difference between static optimized geometries used in quantum chemical modeling and dynamic structures of triplets in MD simulations. © 2015 Wiley Periodicals, Inc. 相似文献
52.
Kimet Jusufi 《中国物理C(英文版)》2023,47(3):035108-035108-9
Using a modified expression for the electric potential in the context of T-duality [Gaete and Nicolini, Phys. Lett. B, 2022], we obtained an exact charged solution within the 4D Einstein-Gauss-Bonnet (4D EGB) theory of gravity in the presence of a cosmological constant. We show that the solution also exists in the regularized 4D EGB theory. Moreover, we point out a correspondence between the black hole solution in the 4D EGB theory and the solution in the non-relativistic Horava–Lifshitz theory. The black hole solution is regular and free from singularity. As a special case, we derive a class of well known solutions in the literature. 相似文献
53.
54.
Analytical theoretical solutions are deduced for the current-potential response, concentration profiles and interfacial potentials of electron-coupled ion transfers in the cyclic voltammetry with thick film-modified electrodes. The theory covers a wide variety of possible situations, namely, the redox transducer can be either immobilized on the working electrode or freely diffusing in the organic film, and the ion transfer can be either simple or complicated by homogeneous chemical processes. A comparative and comprehensive study of each case is performed, establishing the key parameters that define the behaviour of the system, as well as guidelines to analyse its electrochemical signal. 相似文献
55.
《Macromolecular theory and simulations》2017,26(2)
The mechanism of the lower critical solution temperature (LCST) in thermoresponsive polymer solutions has been studied by means of a coarse‐grained single polymer chain simulation and a theoretical approach. The simulation model includes solvent explicitly and thus accounts for solvent interactions and entropy directly. The theoretical model consists of a single chain polymer in an implicit solvent where the effect of solvent is included through the intrapolymer solvophobic potential proposed by Kolomeisky and Widom. The results of this study indicate that the LCST behavior is determined by the competition between the mean energy difference between the bulk and bound solvent, and the entropy loss due to the bound solvent. At low temperatures, solvent molecules are bound to the polymer and the solvophobicity of the polymer is screened, resulting in a coiled state. At high temperatures the entropy loss due to bound solvent offsets the energy gain due to binding which causes the solvent molecules to unbind, leading to the collapse of the polymer chain to a globular state. Furthermore, the coarse‐grained nature of these models indicates that mean interaction energies are sufficient to explain LCST in comparison to specific solvent structural arrangements.
56.
57.
As a first step towards the numerical analysis of the stochastic primitive equations of the atmosphere and the oceans,the time discretization of these equations by an implicit Euler scheme is studied.From the deterministic point of view,the 3D primitive equations are studied in their full form on a general domain and with physically realistic boundary conditions.From the probabilistic viewpoint,this paper deals with a wide class of nonlinear,state dependent,white noise forcings which may be interpreted in either the It6 or the Stratonovich sense.The proof of convergence of the Euler scheme,which is carried out within an abstract framework,covers the equations for the oceans,the atmosphere,the coupled oceanic-atmospheric system as well as other related geophysical equations.The authors obtain the existence of solutions which are weak in both the PDE and probabilistic sense,a result which is new by itself to the best of our knowledge. 相似文献
58.
The authors show that for any e ∈]0,1[,there exists an analytic outside zero solution to a uniformly elliptic conformal Hessian equation in a ball B C R5 which belongs to C1'ε(B) \ C1'ε+(B). 相似文献
59.
Chuanzhong LI 《数学物理学报(B辑英文版)》2017,37(4):1151-1161
In this paper, we construct a new integrable equation called Mbius-Toda equation which is a generalization of q-Toda equation. Meanwhile its soliton solutions are constructed to show its integrable property. Further the Lax pairs of the Mbius-Toda equation and a whole integrable Mbius-Toda hierarchy are also constructed. To show the integrability, the bi-Hamiltonian structure and tau symmetry of the Mbius-Toda hierarchy are given and this leads to the existence of the tau function. 相似文献
60.
We consider a transmission problem consisting of two semilinear parabolic equations involving fractional diffusion operators of different orders in a general non-smooth setting with emphasis on Lipschitz interfaces and transmission conditions along the interface. We give a unified framework for the existence and uniqueness of strong and mild solutions, and their global regularity properties. 相似文献