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171.
用柠檬酸络合法合成了LaMnO3、LaCoO3和LaFeO3.NO分子红外光谱表明在上述化合物中存在不同类型的不饱和配位阳离子.对于LaFeO3来说,不饱和配位Fe2 的出现与表面缺陷有关;对于LaCoO3和LaMnO3表面来说,主要是不饱和配位Me3 与氧的配位性更强. 相似文献
172.
The dissociative adsorption of cyclopropane on the copper surface was studied using quantum chemical molecular dynamics method with “Colors-Excite” code and density functional theory by Amsterdam Density Functional program (ADF2000). The excited state of cyclopropane was used as adsorbate to simulate the dissociated adsorption under an irradiation energy of ca. 10 eV. One of the C-C bonds in cyclopropane was broken and the two new bonds between cyclopropane and copper surface were formed. The electrons transferred from the copper atoms to cyclopropane with a value of about 0.2e. The shorter distances between the carbons and surface copper atoms showed the existence of strong interaction. Consistently, the results indicated metallacyclopentane was the most possible intermediate species in dissociative adsorption by ADF2000 and “Colors-Excite” method. 相似文献
173.
The effects of electron-phonon interaction on energy levels of a polaron in a wurtzite nitride finite parabolic quantum well (PQW) are studied by using a modified Lee-Low-Pines variational method. The ground state, first excited state, and transition energy of the polaron in the GaN/Al0.3Ga0.7N wurtzite PQW are calculated by taking account of the influence of confined LO(TO)-like phonon modes and the half-spaee LO(TO)-like phonon modes and considering the anisotropy of all kinds of phonon modes. The numerical results are given and discussed. The results show that the electron-phonon interaction strongly affects the energy levels of the polaron, and the contributions from phonons to the energy of a polaron in a wurtzite nitride PQW are greater than that in an A1GaAs PQW. This indicates that ehe electron-phonon interaction in a wurtzite nitride PQW is not negligible. 相似文献
174.
We study the spectrum of singular Sturm-Liouville problems with eigenparameter dependent boundary conditions and its approximation with eigenvalues from a sequence of regular problems. 相似文献
175.
The displacement field of an edge dislocation in aluminum was experimentally investigated. Three typical theoretical models were discussed. High-resolution transmission electron microscopy (HRTEM) and geometric phase analysis (GPA) were used to map the displacement field of an edge dislocation. The displacement field near the dislocation core was determined. The experimental show that Peierls-Nabarro model is the most appropriate theoretical model for displacement field of dislocation in aluminum. 相似文献
176.
Using the evolutionary game framework to describe the vaccination behaviors of individuals, this work focuses on the impact of other-regarding tendencies on collective decision-making of vaccination. With extensive computational simulations, we find that when the vaccination cost is small or moderate, the variance of vaccination coverage as well as epidemic size is monotonically depending on the other-regarding effect. However, with a high price of vaccine, a moderate deviation from being entirely self-centered results in a poor communal vaccination benefit. In addition, we also find that the other-regarding effect may lead to an optimal total social cost. 相似文献
177.
以左手材料中产生负磁导率的开口谐振环结构模型为例,从磁导率的定义出发,借助于电磁感应定律,推导了负磁导率的产生过程. 相似文献
178.
Dong-Sheng Hao Jin-Rong Liu Wen-Guang Wu Ju-Cai Yang 《Theoretical chemistry accounts》2009,124(5-6):431-437
The neutral Si n K (n = 2–8) clusters and their anions have been systematically studied by means of the higher level of Gaussian-3 schemes. Equilibrium geometries and electron affinities have been calculated and are discussed for each considered size. For neutral Si n K clusters, the ground state structure is found to be “attaching structure”, in which the K atom is bound to Si n clusters. The most stable isomer for their anions, however, is found to be “substitutional structures”, which is derived from Si(n+1) by replacing the Si atom with a K. The dissociation energies of K atom from the lowest energy structures of Si n K have also been estimated to examine relative stabilities. 相似文献
179.
CHEN Shi-Hua XIAO Jing-Lin 《理论物理通讯》2008,50(12):1287-1289
On the condition of electric-LO phonon strong coupling in unsymmetrical parabolic confinement potential quantum dot (QD), we obtain the eigenenergies of the ground state and the first-excited state, the eigenfunctions of the ground state, and the first-excited state by using variational method of Pekar type. This system in QD may be employed as a two-level quantum system-qubit. When the electron is in the superposition state of the ground state and the first-excited state, we obtain the time evolution of the electron density. The relations both the probability density of electron and the period of oscillation with the electron-LO-phonon coupling strength, the confinement strengths in the xy-plane and the z-direction are discussed. 相似文献
180.
给出了拓扑线性空间中的一个Drop定理.利用此Drop定理,证明了拓扑线性空间中的每个序列紧凸集具有Drop性质;每个可数紧闭凸集具有拟Drop性质.而且结出了拓扑线性空间中Drop性质和拟Drop性质的序列流特征.也讨论了Drop性质和拟Drop性质与泛函取极值之间的联系. 相似文献