全文获取类型
收费全文 | 4397篇 |
免费 | 302篇 |
国内免费 | 196篇 |
专业分类
化学 | 2917篇 |
晶体学 | 70篇 |
力学 | 164篇 |
综合类 | 12篇 |
数学 | 644篇 |
物理学 | 1088篇 |
出版年
2024年 | 5篇 |
2023年 | 56篇 |
2022年 | 102篇 |
2021年 | 124篇 |
2020年 | 138篇 |
2019年 | 156篇 |
2018年 | 171篇 |
2017年 | 140篇 |
2016年 | 208篇 |
2015年 | 165篇 |
2014年 | 221篇 |
2013年 | 414篇 |
2012年 | 315篇 |
2011年 | 328篇 |
2010年 | 266篇 |
2009年 | 197篇 |
2008年 | 278篇 |
2007年 | 250篇 |
2006年 | 193篇 |
2005年 | 158篇 |
2004年 | 115篇 |
2003年 | 98篇 |
2002年 | 109篇 |
2001年 | 77篇 |
2000年 | 66篇 |
1999年 | 41篇 |
1998年 | 46篇 |
1997年 | 45篇 |
1996年 | 42篇 |
1995年 | 38篇 |
1994年 | 33篇 |
1993年 | 27篇 |
1992年 | 31篇 |
1991年 | 16篇 |
1990年 | 26篇 |
1989年 | 22篇 |
1988年 | 16篇 |
1987年 | 19篇 |
1986年 | 12篇 |
1985年 | 18篇 |
1984年 | 26篇 |
1983年 | 14篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1970年 | 4篇 |
排序方式: 共有4895条查询结果,搜索用时 15 毫秒
1.
This paper presents an evaluation of the capability of turbulence models available in the commercial CFD code FLUENT 6.0 for their application to hydrofoil turbulent boundary layer separation flow at high Reynolds numbers. Four widely applied two‐equation RANS turbulence models were assessed through comparison with experimental data at Reynolds numbers of 8.284×106 and 1.657×107. They were the standard k–εmodel, the realizable k–εmodel, the standard k–ωmodel and the shear‐stress‐transport (SST) k–ωmodel. It has found that the realizable k–εturbulence model used with enhanced wall functions and near‐wall modelling techniques, consistently provides superior performance in predicting the flow characteristics around the hydrofoil. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
2.
The implementation of a nonzero-order joint transform correlator using the double port Mach-Zehnder interferometric technique is proposed and demonstrated. This approach provides on-line processing for directly removing the zero-order components of a joint power spectrum in one step and performs the nonzero-order optical correlation. Experimental results are presented and discussed. 相似文献
3.
M. Akdağ 《Acta Mathematica Hungarica》2007,116(1-2):35-45
We define a multifunction F: X ⇝ Y to be upper (lower) D*-supercontinuous if F
+(V) (F
−(V)) is d*-open in X for every open set V of Y. We obtain some characterizations and several properties concerning upper (lower) D*-supercontinuous multifunctions.
相似文献
4.
We extend the previously found accelerated Kerr-Schild metrics for Einstein-Maxwell-null dust and Einstein-Born-Infeld-null dust equations to the cases including the cosmological constant. This way we obtain the generalization of the charged de Sitter metrics in static space-times. We also give a generalization of the zero acceleration limit of our previous Einstein-Maxwell and Einstein-Born-Infeld solutions. 相似文献
5.
Iradj Ouveysi Andrew Wirth Annie Yeh Osman Oğuz 《Annals of Operations Research》2003,124(1-4):285-293
We consider the problem of providing a minimum cost multi-service network subject to one link failure scenarios. We assume our network is fully meshed and demand is satisfied by using direct or two hop-paths. We provide a large scale linear programming formulation and propose and test two effective heuristics. 相似文献
6.
7.
8.
V. V. Sidorchuk J. Skubiszewska-Zięba S. V. Khalameida V. A. Zazhigalov R. Leboda 《Russian Journal of Applied Chemistry》2008,81(8):1325-1331
Effect of conditions of hydrothermal and microwave synthesis of supported vanadium-phosphorus oxide catalysts in an aqueous medium on the physicochemical properties of the vanadyl hydrophosphate obtained was studied. The transformations occurring in the system were examined using X-ray phase and differential-thermal analyses, adsorption-structural method, and scanning electron microscopy. 相似文献
9.
10.
Two novel dithienylethenes with ferrocene units were synthesized by Wittig reaction. The structure of 2a has been established by X‐ray diffraction studies. They could reversibly interconvert between two thermally stable forms, an open and a closed one, using light of different wavelengths as triggers. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献