全文获取类型
收费全文 | 169篇 |
免费 | 15篇 |
国内免费 | 8篇 |
专业分类
化学 | 45篇 |
力学 | 43篇 |
综合类 | 1篇 |
数学 | 16篇 |
物理学 | 87篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 6篇 |
2016年 | 12篇 |
2015年 | 6篇 |
2014年 | 7篇 |
2013年 | 14篇 |
2012年 | 9篇 |
2011年 | 10篇 |
2010年 | 15篇 |
2009年 | 11篇 |
2008年 | 9篇 |
2007年 | 16篇 |
2006年 | 12篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 11篇 |
2002年 | 4篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
排序方式: 共有192条查询结果,搜索用时 0 毫秒
31.
Pieter Vonk Reinoud Noordman Doeke Schippers Bouke Tilstra Hans Wesselingh 《Journal of membrane science》1997,130(1-2):249-263
We present a mathematical model to describe the ultrafiltration behaviour of polymer-electrolyte mixtures. The model combines the proper thermodynamic forces (pressure, chemical potential and electrical potential differences) with multicomponent diffusion theory. The model is verified with experimental data on the ultrafiltration of aqueous solutions of PEG-4000 and potassium phosphate. The single solute rejection of PEG-4000 goes through a maximum as also found by others. The single solute rejection of potassium phosphate depends on the ionic strength of the solution. At low ionic strength rejections are found of 50%. Solutions containing a high concentration of PEG-4000 and potassium phosphate show a negative rejection for potassium phosphate. This is caused by the strongly non-ideal behaviour of these aqueous solutions. The model predicts the behaviour of single solute experiments quite well, but some deviations are found with the mixed solute experiments. However, negative rejections found in the mixed solute experiments are predicted by the model. 相似文献
32.
33.
本文应用正交试验设计改进了麦白霉素的生产工艺,在四个关键环节上选出了比对照组高出700μ/ml以上的高产稳定菌株。该法使试验次数减少,选育周期缩短,既节省了人力物力和降低了生产成本,又增加了麦白霉素药粉的产量,取得了可观的经济效益。 相似文献
34.
35.
36.
37.
38.
39.
Experimental results for various water and air superficial velocities in developing adiabatic horizontal two-phase pipe flow are presented. Flow pattern maps derived from videos exhibit a new boundary line in intermittent regime. This transition from water dominant to water–gas coordinated regimes corresponds to a new transition criterion CT = 2, derived from a generalized representation with the dimensionless coordinates of Taitel and Dukler.Velocity, turbulent kinetic energy and dissipation rate, void fraction and bubble size radial profiles measured at 40 pipe diameters for JL = 4.42 m/s by hot film velocimetry and optical probes confirm this transition: the gas influence is not continuous but strongly increases beyond JG = 0.06 m/s. The maximum dissipation rate, derived from spectra, is increased in two-phase flow by a factor 5 with respect to the single phase case.The axial evolution of the bubble intercept length histograms also reveal the flow organization in horizontal layers, driven by buoyancy effects. Bubble coalescence is attested by a maximum bubble intercept evolving from 2.5 to 4.5 mm along the pipe. Turbulence generated by the bubbles is also manifest by the 4-fold increase of the maximum turbulent dissipation rate along the pipe. 相似文献
40.
Guo-Ping Cai·Long-Xiang Chen Department of Engineering Mechanics State Key Laboratory of Ocean Engineering Shanghai Jiaotong University Shanghai China 《Acta Mechanica Sinica》2010,26(6):951-965
In recent decades,studies on delayed system dynamics have attracted increasing attention and advances have been achieved in stability,nonlinearity,delay identification, delay elimination and application.However,most of the existing work is on the theoretical basis and little is on the experiment.This paper presents our experimental studies on delayed feedback control conducted in recent years with the focus on the discussion of a DSP-based delayed experiment system.Some phenomena in our delay experiments are discussed and a few topics of interest for further research are brought forward. 相似文献