全文获取类型
收费全文 | 30503篇 |
免费 | 3502篇 |
国内免费 | 3998篇 |
专业分类
化学 | 13636篇 |
晶体学 | 119篇 |
力学 | 2239篇 |
综合类 | 349篇 |
数学 | 9650篇 |
物理学 | 12010篇 |
出版年
2024年 | 92篇 |
2023年 | 302篇 |
2022年 | 749篇 |
2021年 | 851篇 |
2020年 | 963篇 |
2019年 | 869篇 |
2018年 | 846篇 |
2017年 | 1010篇 |
2016年 | 1255篇 |
2015年 | 1083篇 |
2014年 | 1653篇 |
2013年 | 2461篇 |
2012年 | 1661篇 |
2011年 | 1949篇 |
2010年 | 1548篇 |
2009年 | 1982篇 |
2008年 | 2001篇 |
2007年 | 2071篇 |
2006年 | 1790篇 |
2005年 | 1567篇 |
2004年 | 1281篇 |
2003年 | 1251篇 |
2002年 | 1090篇 |
2001年 | 866篇 |
2000年 | 862篇 |
1999年 | 727篇 |
1998年 | 690篇 |
1997年 | 526篇 |
1996年 | 380篇 |
1995年 | 357篇 |
1994年 | 300篇 |
1993年 | 275篇 |
1992年 | 253篇 |
1991年 | 210篇 |
1990年 | 222篇 |
1989年 | 215篇 |
1988年 | 186篇 |
1987年 | 174篇 |
1986年 | 149篇 |
1985年 | 168篇 |
1984年 | 152篇 |
1983年 | 90篇 |
1982年 | 121篇 |
1981年 | 112篇 |
1980年 | 98篇 |
1979年 | 101篇 |
1978年 | 78篇 |
1977年 | 76篇 |
1976年 | 70篇 |
1973年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
V. P. Maslov 《Theoretical and Mathematical Physics》2007,150(1):102-122
From the standpoint of thermodynamic averaging of fission microprocesses, we investigate the origin of radioactive release
in an NPP after an accident or after resource depletion. The genesis of the NPP release is interpreted as a new thermodynamic
phenomenon, a zeroth-order phase transition. This problem setting results in a problem in probabilistic number theory. We
prove the corresponding theorem leading to quantization of the Zipf law for the frequency of a zeroth-order phase transition
with different values of the jump of the Gibbs thermodynamic potential. We introduce the notion of hole dimension.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 150, No. 1, pp. 118–142, January, 2007. 相似文献
82.
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
83.
1846年,刘维尔在自己主办的杂志“纯粹与应用数学杂志”首次出版了伽罗瓦的数学研究,这对于伽罗瓦理论的传播与发展是具有决定意义的事件.伽罗瓦去世14年后,刘维尔发表伽罗瓦数学研究的原因是什么?采用数学历史文献分析法,得出四个重要原因:①伽罗瓦的朋友和弟弟的请求;②力图弥补科学院曾经造成的不公正;③刘维尔积极扶持年轻人的高贵品质使然;④刘维尔与利布里学术论战的促进. 相似文献
84.
M. Iuga G. Steinle-Neumann J. Meinhardt 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(2):127-133
Athermal elasticity for some ceramic materials (α-Al2O3,
SiC (α and β phases), TiO2 (rutile and anatase),
hexagonal AlN and TiB2, cubic BN and CaF2, and monoclinic
ZrO2) have been investigated via density functional theory.
Energy-volume equation-of-state computations to obtain the zero pressure
equilibrium volume and bulk modulus as well as computations of the full
elastic constant tensor of these ceramics at the experimental zero pressure
volume have been performed. The present results for the single crystal
elasticity are in good agreement with experiments both for the aggregate
properties (bulk and shear modulus) and the elastic anisotropy. In contrast,
a considerable discrepancy for the zero pressure bulk modulus of some
ceramics evaluated from the energy-volume fit to the computational zero
pressure volume has been observed. 相似文献
85.
Within the framework of free interaction theory numerical methods are used to investigate the occurrence of supersonic zones with shocks in the outer inviscid region for flow past roughness in the lower viscous sublayer, with and without the formation of local separation zones. 相似文献
86.
87.
用庞小峰先生提出的生物能量传递的新理论和 Runge-Kutta数值模拟方法,研究了三通道α-螺旋蛋白质中激发的孤子的动力学特性,求出在0K和300K温度下该孤子稳定地沿蛋白质链传递.由此可见,它能担任在蛋白质分子中传递生物能量的功能.从而再次证实了新理论的可利用性. 相似文献
88.
本文针对单件小批量生产系统 ,建立了模糊优化的动态随机投入产出模型 ,同时给出了该模型的递推解法 ,并用此模型对某单件小批企业在生产计划期的商品量进行了规划 相似文献
89.
Jesús M. Velásquez Bermúdez 《Annals of Operations Research》2002,117(1-4):21-31
This document presents theoretical considerations about the solution of dynamic optimization problems integrating the Benders Theory, the Dynamic Programming approach and the concepts of Control Theory. The so called Generalized Dual Dynamic Programming Theory (GDDP) can be considered as an extension of two previous approaches known as Dual Dynamic Programming (DDP): The first is the work developed by Pereira and Pinto [3–5], which was revised by Velásquez and others [8,9]. The second is the work developed by Read and others [2,6,7]. 相似文献
90.
A new method for rotation and brightness invariant pattern recognition was proposed by applying multiple circular harmonic expansions to the joint transform correlator. The amplitudes of the multiple orders of circular harmonic expansions made from a detecting image were synthetically modified to respond to the same auto-correlation peaks. These modified circular harmonic expansions were arranged in the input plane as reference patterns together with an arbitrary target pattern, and the correlation signals between them were calculated in the subtracted joint transform correlator. The fraction of the correlation-peak intensities between the target and the references were extracted as a new discrimination parameter. This new parameter performs pattern recognition under rotation and brightness invariance with good discriminability. Its high discriminability has been proved in computer simulations using the face image patterns of many individuals. 相似文献