全文获取类型
收费全文 | 9756篇 |
免费 | 385篇 |
国内免费 | 415篇 |
专业分类
化学 | 2104篇 |
晶体学 | 20篇 |
力学 | 4021篇 |
综合类 | 34篇 |
数学 | 1416篇 |
物理学 | 2961篇 |
出版年
2024年 | 14篇 |
2023年 | 144篇 |
2022年 | 107篇 |
2021年 | 115篇 |
2020年 | 182篇 |
2019年 | 159篇 |
2018年 | 109篇 |
2017年 | 196篇 |
2016年 | 351篇 |
2015年 | 322篇 |
2014年 | 412篇 |
2013年 | 542篇 |
2012年 | 379篇 |
2011年 | 549篇 |
2010年 | 385篇 |
2009年 | 637篇 |
2008年 | 650篇 |
2007年 | 660篇 |
2006年 | 572篇 |
2005年 | 543篇 |
2004年 | 497篇 |
2003年 | 467篇 |
2002年 | 369篇 |
2001年 | 239篇 |
2000年 | 259篇 |
1999年 | 191篇 |
1998年 | 237篇 |
1997年 | 168篇 |
1996年 | 117篇 |
1995年 | 161篇 |
1994年 | 130篇 |
1993年 | 108篇 |
1992年 | 88篇 |
1991年 | 62篇 |
1990年 | 40篇 |
1989年 | 63篇 |
1988年 | 53篇 |
1987年 | 36篇 |
1986年 | 31篇 |
1985年 | 24篇 |
1984年 | 24篇 |
1983年 | 11篇 |
1982年 | 21篇 |
1981年 | 14篇 |
1979年 | 26篇 |
1978年 | 10篇 |
1977年 | 13篇 |
1976年 | 10篇 |
1973年 | 10篇 |
1971年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
31.
Louis Marchildon 《Foundations of Physics》2004,34(1):59-73
In a recently proposed interpretation of quantum mechanics, U. Mohrhoff advocates original and thought-provoking views on space and time, the definition of macroscopic objects, and the meaning of probability statements. The interpretation also addresses a number of questions about factual events and the nature of reality. The purpose of this note is to examine several issues raised by Mohrhoff's interpretation, and to assess whether it helps providing solutions to the long-standing problems of quantum mechanics. 相似文献
32.
A review of the optimal stopping problem with more than a single decision maker (DM) is presented in this paper. We classify
the existing literature according to the arrival of the offers, the utility of the DMs, the length of the sequence of offers,
the nature of the game and the number of offers to be selected. We enumerate various definitions for this problem and describe
some dynamic approaches.
Fouad Ben Abdelaziz is on leave from the Institut Superieur de Gestion, University of Tunis, Tunisia e-mail: foued.benabdelaz@isg.run.tn. 相似文献
33.
The steady-state two-phase flow non-linear equation is considered in the case when one of phases has low effective permeability in some periodic set, while on the complementary set it is high; the second phase has no contrast of permeabilities in different zones. A homogenization procedure gives the homogenized model with macroscopic effective permeability of the second phase depending on the gradient and on the second order derivatives of the macroscopic pressure of the first phase. This effect cannot be obtained by classical (one small parameter) homogenization. To cite this article: G.P. Panasenko, G. Virnovsky, C. R. Mecanique 331 (2003). 相似文献
34.
A. Vukics H. Ritsch 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(3):585-599
We present a framework for efficiently performing Monte Carlo
wave-function simulations in cavity QED with moving particles. It
relies heavily on the object-oriented programming paradigm as realised
in C++, and is extensible and applicable for simulating open
interacting qua
ntum dynamics in general. The user is provided with a
number of “elements”, e.g. pumped moving particles, pumped lossy
cavity modes, and various interactions to compose complex interacting
systems, which contain several particles moving in electromagnetic
fields of various configurations, and perform wave-function
simulations on such systems. A number of tools are provided to
facilitate the implementation of new elements. 相似文献
35.
Thiw work is concerned with the formulation of constituent interactions and corresponding balance relations in classical mixture theory as based on a model for the (classical) constituent structure of such a mixture. 相似文献
36.
J. Schulte 《Journal of statistical physics》1993,70(5-6):1343-1347
The thermodynamic stability of4He4–13 at 3.2 K is investigated with the classical Monte Carlo method, with the semiclassical path-integral Monte Carlo (PIMC) method, and with the semiclassical all-order many-body method. In the all-order many-body simulation the dipole-dipole approximation including short-range correction is used. The resulting stability plots are discussed and related to recent TOF experiments by Stephens and King. It is found that with classical Monte Carlo of course the characteristics of the measured mass spectrum cannot be resolved. With PIMC, switching on more and more quantum mechanics. by raising the number of virtual time steps results in more structure in the stability plot, but this did not lead to sufficient agreement with the TOF experiment. Only the all-order many-body method resolved the characteristic structures of the measured mass spectrum, including magic numbers. The result shows the influence of quantum statistics and quantum mechanics on the stability of small neutral helium clusters. 相似文献
37.
This paper deals with the optimal control of a one-machine two-product manufacturing system with setup changes, operating in a continuous time dynamic environment. The system is deterministic. When production is switched from one product to the other, a known constant setup time and a setup cost are incurred. Each product has specified constant processing time and constant demand rate, as well as an infinite supply of raw material. The problem is formulated as a feedback control problem. The objective is to minimize the total backlog, inventory and setup costs incurred over a finite horizon. The optimal solution provides the optimal production rate and setup switching epochs as a function of the state of the system (backlog and inventory levels). For the steady state, the optimal cyclic schedule is determined. To solve the transient case, the system's state space is partitioned into mutually exclusive regions such that with each region, the optimal control policy is determined analytically. 相似文献
38.
T. Charitat B. Fourcade 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,1(3):333-336
An o-ring takes spontaneously the shape of a chair when strong enough torsion is applied in its tangent plane. This state
is metastable, since work has to be done on the o-ring to return to the circular shape. We show that this metastable state
exists in a Hamiltonian where curvature and torsion are coupled via an intrinsic curvature term. If the o-ring is constrained to be planar (2d case), this metastable state displays a kink-anti-kink
pair. This state is metastable if the ratio is less than , where C and A are the torsion and the bending elastic constants [#!landau!#]. In three dimensions, our variational approach shows that
. This model can be generalized to the case where the bend is induced by a concentration field which follows the variations
of the curvature.
Received: 27 August 1997 / Revised: 23 October 1997 / Accepted: 12 November 1997 相似文献
39.
An initial boundary value problem for the dynamic system of anisotropic elasticity in a half space is studied in the paper. A novel method of finding an exact solution of this problem for a special polynomial form of initial data and inhomogeneous term of the system is described. On the base of this method the simulation of elastic waves in different homogeneous anisotropic half spaces is implemented. 相似文献
40.
This paper proposes a floating-point genetic algorithm (FPGA) to solve the unit commitment problem (UCP). Based on the characteristics of typical load demand, a floating-point chromosome representation and an encoding–decoding scheme are designed to reduce the complexities in handling the minimum up/down time limits. Strategic parameters of the FPGA are characterized in detail, i.e., the evaluation function and its constraints, population size, operation styles of selection, crossover operation and probability, mutation operation and probability. A dynamic combination scheme of genetic operators is formulated to explore and exploit the FPGA in the non-convex solution space and multimodal objective function. Experiment results show that the FPGA is a more effective technique among the various styles of genetic algorithms, which can be applied to the practical scheduling tasks in utility power systems. 相似文献