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151.
We study the fate of the Onsager-Casimir reciprocity relations for a continuous system when some of its variables are eliminated adiabatically. Just as for discrete systems, deviations appear in correction terms to the reduced evolution equation that are of higher order in the time scale ratio. The deviations are not removed by including correction terms to the coarse-grained thermodynamic potential. However, via a reformulation of the theory, in which the central role of the thermodynamic potential is taken over by an associated Lagrangian-type expression, we arrive at a modified form of the Onsager-Casimir relations that survives the adiabatic elimination procedure. There is a simple relation between the time evolution of the redefined thermodynamic forces and that of the basic thermodynamic variables; this relation also survives the adiabatic elimination. The formalism is illustrated by explicit calculations for the Klein-Kramers equation, which describes the phase space distribution of Brownian particles, and for the corrected Smoluchowski equation derived from it by adiabatic elimination of the velocity variable. The symmetry relation for the latter leads to a simple proof that the reality of the eigenvalues of the simple Smoluchowski equation is not destroyed by the addition of higher order corrections, at least not within the framework of a formal perturbation expansion in the time scale ratio. 相似文献
152.
A model forN-N interaction proposed earlier by two of us (VSB and VKG), has been extended to incorporate the tensor component of the nuclear
force. Based on the quark compound bag model (QCB), the nucleon-nucleon potential has a short range repulsive core which is
non-local and has a characteristic energy dependence and is expressed in terms of the parameters relating to the six-quark
compound bag. To account for the low energy properties, this repulsive core interaction is supplemented by a phenomenological
non-local potential containing both central (S-wave) and tensor components and operates only outside the QCB. Using this model, we analyse and compare the results with
the experimental data for the electromagnetic form factors of the deuteron, theD-state observables, such as the quadrupole moment, theD-state probability, and theD/S ratio along with then-p scattering phase shifts up to about 400 MeV. 相似文献
153.
154.
Complementary energy principle for large elastic deformation 总被引:1,自引:0,他引:1
GAO Yuchen 《中国科学G辑(英文版)》2006,49(3):341-356
Using the “base forces” as the fundamental unknowns to determine the state of an elastic system, the complementary energy
principle for large elastic deformation is constructed for the conjugate quantities being displacement gradients, which possesses
exactly the same form as that of classical linear elasticity. It is revealed that the complementary energy contains deformation
part and rotation part. 相似文献
155.
Rubbers are usually compounded with different chemicals and fillers in order to modify their properties to suit the end applications. Natural rubber (NR) contains different natural occurring materials and this brings about subtle complexities in controlling compound and vulcanizate properties. Thus, the aim of this paper is to illustrate that the properties of compounds and vulcanizates of NR/clay prepared from fresh field latex and from concentrated latex are different. Different amounts of pristine clay were added to the two latices and their viscosity determined. The latex mixtures were next coagulated to form solid filled rubbers and their properties examined. Vulcanizates of these solid rubbers were then prepared and their properties, also, were determined. The cause of an observed variation is attributed to soluble proteins in the fresh field latex. Structural models to explain this are proposed. 相似文献
156.
《Journal of computational chemistry》2017,38(21):1869-1878
In this work, we present scaled variants of the DLPNO‐CCSD(T) method, dubbed as (LS)DLPNO‐CCSD(T) and (NS)DLPNO‐CCSD(T), to obtain accurate interaction energies in supramolecular complexes governed by noncovalent interactions. The novel scaled schemes are based on the linear combination of the DLPNO‐CCSD(T) correlation energies calculated with the standard (LoosePNO and NormalPNO) and modified (Loose2PNO and Normal2PNO) DLPNO‐CCSD(T) accuracy levels. The scaled DLPNO‐CCSD(T) variants provide nearly TightPNO accuracy, which is essential for the quantification of weak noncovalent interactions, with a noticeable saving in computational cost. Importantly, the accuracy of the proposed schemes is preserved irrespective of the nature and strength of the supramolecular interaction. The (LS)DLPNO‐CCSD(T) and (NS)DLPNO‐CCSD(T) protocols have been used to study in depth the role of the CH–π versus π–π interactions in the supramolecular complex formed by the electron‐donor truxene‐tetrathiafulvalene (truxTTF) and the electron‐acceptor hemifullerene (C30H12). (NS)DLPNO‐CCSD(T)/CBS calculations clearly reveal the higher stability of staggered (dominated by CH–π interactions) versus bowl‐in‐bowl (dominated by π–π interactions) arrangements in the truxTTF•C30H12 heterodimer. Hemifullerene and similar carbon‐based buckybowls are therefore expected to self‐assemble with donor compounds in a richer way other than the typical concave–convex π–π arrangement found in fullerene‐based aggregates. © 2017 Wiley Periodicals, Inc. 相似文献
157.
本文提出了常水深环境下中厚度圆浮板自由振动的一个解析解.分析中考虑了板横向剪切变形的影响和横截面转动惯性效应,利用空气中中厚度圆板的振型叠加和势流理论,导得了浮板系统频率方程的解析式.由此可看出Y.Tanaka得到的圆形薄浮板的解是本文的特例.最后数值计算还给出了水深和钢缆刚度与频率的关系曲线.并指出了h/a在什么范围可以略去剪切变形和转动惯量的影响. 相似文献
158.
Efficient Evaluation of the Elastic Forces and the Jacobian in the Absolute Nodal Coordinate Formulation 总被引:1,自引:0,他引:1
This paper develops a new procedure for evaluating the elastic forces, the elastic energy and the jacobian of the elastic
forces in the absolute nodal coordinate formulation. For this procedure, it is fundamental to use some invariant sparse matrices
that are integrated in advance and have the property of transforming the evaluation of the elastic forces in a matrix multiplication
process. The use of the invariant matrices avoids the integration over the volume of the element for every evaluation of the
elastic forces. Great advantages can be achieved from these invariant matrices when evaluating the elastic energy and calculating
the jacobian of the elastic forces as well. The exact expression of the jacobian of the differential system of equations of
motion is obtained, and some advantages of using the absolute nodal coordinate formulation are pointed out. Numerical results
show that there is important time saving as a result of the use of the invariant matrices. 相似文献
159.
The equilibrium constants [K=anti/syn] of a pair of atropisomers due to restricted rotation about Csp3-Csp2 bond for [2-(2-hydroxynaphthalen-1-yl)-3,3-dimethylindolin-1-yl](4-substituted phenyl)methanone were determined in some solvents. The presence of the effective π-π interaction was demonstrated by the correlation between the equilibrium constants (K) and the substituent effect of the phenyl groups (σp), suggesting that the ‘neutral-type’ interaction is operative. 相似文献
160.
It is shown that in LC of polymers, the interaction parameter in ternary mobile phases can be described by a plane, which is determined by the dependencies in binary mobile phases. Instead of a critical adsorption point, critical conditions are observed along a straight line of composition between the two critical points in binary mobile phases. Consequently, a separation of block copolymers under critical conditions for one block by an adsorption mechanism for the other block can be achieved in ternary mobile phases of different compositions, which allows an adjustment of the retention of the adsorbing block. 相似文献