全文获取类型
收费全文 | 1523篇 |
免费 | 76篇 |
国内免费 | 72篇 |
专业分类
化学 | 132篇 |
力学 | 33篇 |
综合类 | 3篇 |
数学 | 1382篇 |
物理学 | 121篇 |
出版年
2024年 | 4篇 |
2023年 | 22篇 |
2022年 | 23篇 |
2021年 | 23篇 |
2020年 | 34篇 |
2019年 | 41篇 |
2018年 | 41篇 |
2017年 | 38篇 |
2016年 | 27篇 |
2015年 | 45篇 |
2014年 | 69篇 |
2013年 | 139篇 |
2012年 | 49篇 |
2011年 | 93篇 |
2010年 | 69篇 |
2009年 | 110篇 |
2008年 | 118篇 |
2007年 | 118篇 |
2006年 | 85篇 |
2005年 | 63篇 |
2004年 | 63篇 |
2003年 | 50篇 |
2002年 | 36篇 |
2001年 | 37篇 |
2000年 | 33篇 |
1999年 | 23篇 |
1998年 | 37篇 |
1997年 | 32篇 |
1996年 | 16篇 |
1995年 | 15篇 |
1994年 | 19篇 |
1993年 | 13篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 1篇 |
排序方式: 共有1671条查询结果,搜索用时 15 毫秒
91.
About the compatibility between ansatzes and constraints for a local formulation of orbital‐free density functional theory
下载免费PDF全文
![点击此处可从《International journal of quantum chemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Functional properties that are exact for the Hohenberg–Kohn functional may turn into mutually exclusive constraints at a given level of ansatz. This is exemplarily shown for the local density approximation. Nevertheless, it is possible to reach exactly the Kohn–Sham data from an orbital‐free density functional framework based on simple one‐point functionals by starting from the Levy–Perdew–Sahni formulation. The energy value is obtained from the density‐potential pair, and therefore does not refer to the functional dependence of the potential expression. Consequently, the potential expression can be obtained from any suitable model and is not required to follow proper scaling behavior. 相似文献
92.
The exact Fermi potential yielding the Hartree–Fock electron density from orbital‐free density functional theory
下载免费PDF全文
![点击此处可从《International journal of quantum chemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The exact expression for the Fermi potential yielding the Hartree–Fock electron density within an orbital‐free density functional formalism is derived. The Fermi potential, which is defined as that part of the potential that depends on the particles’ nature, is in this context given as the sum of the Pauli potential and the exchange potential. The exact exchange potential for an orbital‐free density functional formalism is shown to be the Slater potential. 相似文献
93.
Similarity solutions for the flow of a non-ideal gas behind a strong exponential shock driven out by a piston (cylindrical
or spherical) moving with time according to an exponential law are obtained. Similarity solutions exist only when the surrounding
medium is of constant density. Solutions are obtained, in both the cases, when the flow between the shock and the piston is
isothermal or adiabatic. It is found that the assumption of zero temperature gradient brings a profound change in the density
distribution as compare to that of the adiabatic case. Effects of the non-idealness of the gas on the flow-field between the
shock and the piston are investigated. The variations of density-ratio across the shock and the location of the piston with
the parameter of non-idealness of the gas are also obtained. 相似文献
94.
In the first part of this paper we give suitable spectral properties of the adjoint operators induced by appropriate perturbations of some hyperbolic linear vector fields. These properties are useful to prove general facts based on the Nash–Moser inverse function theorem. In the second part of this work we study circumstances where a global linearization of a vector field X in a real numerical space is feasible and where some diffeomorphisms which are close to exp(X) can be embedded in a flow. 相似文献
95.
《Applied Mathematical Modelling》2014,38(5-6):1698-1709
We consider Bayesian estimation of the stress–strength reliability based on record values. The estimators are derived under the squared error loss function in the one parameter as well as two-parameter exponential distributions. The Bayes estimators are derived, in some cases in closed form, and their performance is investigated in terms of their bias and mean squared errors and compared with the maximum likelihood estimators. An illustrative example is given. 相似文献
96.
We study the stability of a robot system composed of two Euler–Bernoulli beams with non-collocated controllers. By the detailed spectral analysis, we prove that the asymptotical spectra of the system are distributed in the complex left-half plane and there is a sequence of the generalized eigenfunctions that forms a Riesz basis in the energy space. Since there exist at most finitely many spectral points of the system in the right half-plane, to obtain the exponential stability, we show that one can choose suitable feedback gains such that all eigenvalues of the system are located in the left half-plane. Hence the Riesz basis property ensures that the system is exponentially stable. Finally we give some simulation for spectra of the system. 相似文献
97.
We show that the equality m1(f(x))=m2(g(x)) for x in a neighborhood of a point a remains valid for all x provided that f and g are open holomorphic maps, f(a)=g(a)=0 and m1,m2 are Minkowski functionals of bounded balanced domains. Moreover, a polynomial relation between f and g is obtained. 相似文献
98.
In this paper, we consider a second order evolution equation in a Banach space, which can model an elastic system with structural damping. New forms of the corresponding first order evolution equation are introduced, and their well-posed property is proved by means of the operator semigroup theory. We give sufficient conditions for analyticity and exponential stability of the associated semigroups. 相似文献
99.
This paper deals with the linear theory of isotropic micropolar thermoviscoelastic materials. When the dissipation is positive definite, we present two uniqueness theorems. The first one requires the extra assumption that some coupling terms vanish; in this case, the instability of solutions is also proved. When the internal energy and the dissipation are both positive definite, we prove the well-posedness of the problem and the analyticity of the solutions. Exponential decay and impossibility of localization are corollaries of the analyticity. 相似文献
100.
In this paper we consider a thermoelastic system of type III with boundary distributed delay. Under suitable assumption on the weight of the delay, we prove, using the energy method, that the damping effect through heat conduction given by Green and Naghdi's theory is still strong enough to uniformly stabilize the system even in the presence of time delay. 相似文献