全文获取类型
收费全文 | 8622篇 |
免费 | 178篇 |
国内免费 | 14篇 |
专业分类
化学 | 4839篇 |
晶体学 | 198篇 |
力学 | 196篇 |
数学 | 1410篇 |
物理学 | 2171篇 |
出版年
2022年 | 150篇 |
2021年 | 173篇 |
2020年 | 120篇 |
2019年 | 153篇 |
2018年 | 167篇 |
2017年 | 153篇 |
2016年 | 279篇 |
2015年 | 212篇 |
2014年 | 294篇 |
2013年 | 665篇 |
2012年 | 432篇 |
2011年 | 487篇 |
2010年 | 394篇 |
2009年 | 354篇 |
2008年 | 403篇 |
2007年 | 387篇 |
2006年 | 328篇 |
2005年 | 287篇 |
2004年 | 271篇 |
2003年 | 262篇 |
2002年 | 218篇 |
2001年 | 167篇 |
2000年 | 150篇 |
1999年 | 116篇 |
1998年 | 120篇 |
1997年 | 95篇 |
1996年 | 96篇 |
1995年 | 120篇 |
1994年 | 75篇 |
1993年 | 60篇 |
1992年 | 80篇 |
1991年 | 54篇 |
1990年 | 76篇 |
1989年 | 72篇 |
1988年 | 72篇 |
1987年 | 62篇 |
1986年 | 70篇 |
1985年 | 106篇 |
1984年 | 121篇 |
1983年 | 70篇 |
1982年 | 71篇 |
1981年 | 80篇 |
1980年 | 86篇 |
1979年 | 58篇 |
1978年 | 66篇 |
1977年 | 72篇 |
1976年 | 64篇 |
1975年 | 59篇 |
1974年 | 50篇 |
1973年 | 43篇 |
排序方式: 共有8814条查询结果,搜索用时 15 毫秒
931.
Piotr Jeleń Magdalena Szumera Magdalena Gawęda Elżbieta Długoń Maciej Sitarz 《Journal of Thermal Analysis and Calorimetry》2017,129(1):103-108
Heat capacity of single-crystal samples of five chalcogenides (LiInS2, LiInSe2, LiGaS2, LiGaSe2, and LiGaTe2) was measured with DSC in a temperature range from 180 to 460 K. The data for LiInS2 and LiInSe2 were compared with the literature data and shown to agree with the results of adiabatic calorimetry (Gmelin and Hönle in Thermochimica Acta 269: 575–590, 1995) better than with other DSC data (Kühn et al. in Cryst Res Technol 22: 265–269, 1987). Besides, the high-temperature fitting polynomial for C P(T) published about 30 years ago for LiInS2 is wrong. LiGaS2, LiGaSe2, and LiGaTe2 were measured for the first time. 相似文献
932.
Krzysztof Dȩbicki Peng Liu Michel Mandjes Iwona Sierpińska-Tułacz 《Queueing Systems》2017,85(3-4):249-267
In this paper, we derive exact large buffer asymptotics for a two-class generalized processor sharing (GPS) model, under the assumption that the input traffic streams generated by both classes correspond to heavy-tailed Lévy processes. Four scenarios need to be distinguished, which differ in terms of (i) the level of heavy-tailedness of the driving Lévy processes as well as (ii) the values of the corresponding mean rates relative to the GPS weights. The derived results are illustrated by two important special cases, in which the queues’ inputs are modeled by heavy-tailed compound Poisson processes and by \(\alpha \)-stable Lévy motions. 相似文献
933.
Adrian Falkowski Leszek Słomiński 《Stochastic Processes and their Applications》2017,127(11):3536-3557
We study the existence, uniqueness and stability of solutions of general stochastic differential equations with constraints driven by semimartingales and processes with bounded -variation. Applications to SDEs with constraints driven by fractional Brownian motion and standard Brownian motion are given. 相似文献
934.
A weighting of the edges of a hypergraph is called vertex‐coloring if the weighted degrees of the vertices yield a proper coloring of the graph, i.e. every edge contains at least two vertices with different weighted degrees. In this article, we show that such a weighting is possible from the weight set for all hypergraphs with maximum edge size and not containing edges solely consisting of identical vertices. The number is best possible for this statement. 相似文献
935.
This paper presents the results of an experimental study on the heat transfer and pressure drop in diagonally finned tube banks. The investigations have been carried out using the napthalene analogy. The performance of a heat exchanger with fins arranged a certain angle to the flow direction with the plain tube heat exchanger have been compared. 相似文献
936.
E. Wierzbicki Cz. Woźniak L. Łacińska 《Archive of Applied Mechanics (Ingenieur Archiv)》2005,74(9):618-628
Two problems will be studied in this contribution. First, we analyse some phenomena which take place in a laminated solid and are caused by a fluctuation of time-dependent boundary tractions. Second, we investigate the transient effect of initial displacement fluctuations on the behaviour of a laminate. To solve the above problems we propose a new macroscopic 3D model for investigations of initial-boundary value problems in elastodynamics of a laminated medium. 相似文献
937.
A class of nonlinear viscoelastic constitutive equations including the K-BKZ constitutive equations, linear viscoelasticity and the Green-Rivlin models is developed. A stored-energy functional is associated with each model in such a way that the energy dissipation rate is non-negative. The theory is developed for 1D viscoelasticity and extended to 3D viscoelastic media. 相似文献
938.
Relations Between Relaxation Modulus and Creep Compliance in Anisotropic Linear Viscoelasticity 总被引:2,自引:0,他引:2
The results obtained previously for scalar and class P completely monotone relaxation moduli are extended to arbitrary anisotropy.
It is shown for general anisotropic viscoelastic media that, if the relaxation modulus is a locally integrable completely
monotone function, then the creep compliance is a Bernstein function and conversely. The elastic and equilibrium limits of
the two material functions are related to each other. The relaxation modulus or its derivative can be singular at 0. A rigorous
general formulation of the relaxation spectrum in an anisotropic viscoelastic medium is given. The effect of Newtonian viscosity
on creep compliance is examined.
Put some makeup on him and lay him to rest. Anonymous 相似文献
939.
The self-consistent model of heat and mass transfer during convective drying of capillary porous media describing both the
first and the second periods of drying is presented in Musielak (Wydawnictwo Politechniki Poznańskiej, seria Rozprawy, nr
386 (2004a); Chem. Process Eng. 25, 393–409 (2004b)). The results of simulations of processes in steady conditions are shown (Musielak Wydawnictwo Politechniki
Poznańskiej, seria Rozprawy, nr 386 (2004a); Chem. Process Eng. 25, 393–409 (2004b)). The main aim of the present work is to compare experimental results with those from numerical simulations.
Three convective drying processes have been performed experimentally. The first and the second periods of drying are considered,
during which the humidity of air in the dryer changes due to evaporation. The first process is used to establish drying parameters,
whereafter the two remaining processes are simulated. Good agreement between experimental and simulation results is found,
both qualitative and quantitative. 相似文献
940.
The paper is concerned with measurements of rheological properties of fermentation broth. An on-line rheometer, Rheohelix-1, based on the application of a helical screw impeller rotating in a draught tube has been constructed. The instrument was used for measurements of the rheological parameters of fermentation broth of Aspergillus niger in a submerged fermentation process. The results of rheological and some standard measurements have been compared and proved the applicability of the instrument.Presented at the Golden Jubilee Conference of the British Society of Rheology and Third European Rheology Conference, Edinburgh, 3–7 September, 1990. 相似文献