全文获取类型
收费全文 | 344篇 |
免费 | 0篇 |
专业分类
化学 | 188篇 |
晶体学 | 3篇 |
力学 | 7篇 |
数学 | 59篇 |
物理学 | 87篇 |
出版年
2023年 | 4篇 |
2020年 | 11篇 |
2019年 | 7篇 |
2017年 | 3篇 |
2014年 | 3篇 |
2013年 | 16篇 |
2012年 | 17篇 |
2011年 | 18篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 10篇 |
2007年 | 11篇 |
2006年 | 15篇 |
2005年 | 12篇 |
2004年 | 10篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 11篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 10篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1973年 | 2篇 |
1972年 | 5篇 |
1971年 | 10篇 |
1970年 | 8篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1936年 | 2篇 |
排序方式: 共有344条查询结果,搜索用时 125 毫秒
21.
The effect of shear flow on the phase behaviour of partially miscible blends exhibiting a lower critical solution temperature behaviour has been investigated. Miscibility limits were detected, with and without the application of flow, as changes from optical clarity to turbidity using light scattering and as the appearance of double glass transition temperatures. Light scattering data were collected on a rheo-optical device that was designed to monitor phase changes in polymer blends undergoing shear flow between parallel glass plates in a temperature controlled environment. Glass transition temperatures of some quenched sheared blends were measured using a differential scanning calorimeter in order to confirm the conclusions from the light scattering data. It was found that shear induced demixing and shear induced mixing may be observed within the same blend depending on the magnitude of the applied flow. Miscibility gaps and closed miscibility loops may appear in the phase diagrams. At certain temperatures and shear rates unusual scattering patterns were observed and these were associated with a “ripple” morphology when directly viewed through the microscope. 相似文献
22.
Higgins AM Sferrazza M Jones RA Jukes PC Sharp JS Dryden LE Webster J 《The European physical journal. E, Soft matter》2002,8(2):137-143
We investigate the dynamics of spinodal dewetting in liquid-liquid polymer systems. Dewetting of poly(methyl-methacrylate)
(PMMA) thin films on polystyrene (PS) “substrates” is followed in situ using neutron reflectivity. By following the development of roughness at the PS/PMMA interface and the PMMA surface we extract
characteristic growth times for the dewetting process. These characteristic growth times are measured as a function of the
molecular weight of the two polymers. By also carrying out experiments in the regime where the dynamics are independent of
the PS molecular weight, we are able to use dewetting to probe the scaling of the PMMA thin film viscosity with temperature
and molecular weight. We find that this scaling reflects bulk behaviour. However, absolute values are low compared to bulk
viscosities, which we suggest may be due in part to slippage at the polymer/polymer interface.
Received 25 June 2001 and Received in final form 5 December 2001 相似文献
23.
24.
Cooley NM Higgins JT Holmes MG Attridge TH 《Journal of photochemistry and photobiology. B, Biology》2001,60(2-3):143-150
The effects of supplementary ultraviolet-A (UV-A) and ultraviolet-B+A (UV-B+A) in the natural environment on the growth and morphology of various ecotypes of Arabidopsis thaliana were investigated. The ecotypes investigated were Columbia (Col-4), Landsberg erecta (Ler-0), Cvi-0, Wassilewskija, Enkheim-D, Aa-0 and Di-1. The mutant hy-4 was also used. Results varied with the radiation treatment, ecotype and parameter measured. Plants subjected to elevated UV-A were both insensitive (all parameters Cvi-0 and Col-4) and sensitive. When responses to UV-A occurred they were mostly inhibitory (all significant responses of Di-1 and Enkheim-D, most parameters of Wassilewskija, and some parameters of hy-4), however, promotive affects were observed for some parameters of Aa-0 and Ler-0. Supplementary UV-B+A inhibited all parameters of Di-1 and Enkheim-D and most parameters of Col-4, Ler-0 and hy-4, but Wassilewskija, Aa-0 and Cvi-0 were mostly insensitive. The magnitude of the UV-B+A response varied with ecotype (compare Di-1 with Ler-0). Some ecotypes were sensitive to UV-A but not UV-B+A (Aa-0), whereas others (Ler-0, Col-4) show the opposite sensitivities. A linear relationship is reported between the degree of UV-B+A inhibition of each ecotype and growth rate. The higher the growth rate the more susceptible the ecotype is to UV-B+A inhibition. This relationship holds for the majority of growth parameters measured. 相似文献
25.
van Enk SJ 《Physical review letters》2000,84(4):789; author reply 790
26.
Ohne Zusammenfassung 相似文献
27.
Christina H. Chen Ashil K. Higgins Reinhold M. Strnat 《Journal of magnetism and magnetic materials》2008
The effect of specimen geometry on magnetization distortion in closed-circuit measurements is reported in this letter. The degree of the distortion increases as the ratio of length to diameter (L/D) of specimen decreases, and the distortion can reduce the magnetization values as much as 42% when the applied magnetic field is 24 kOe and the L/D is 0.28. The type of magnetic material also affects the distortion. Although the phenomenon seems to be similar to the “image effect” that occurs in open-circuit measurements, reports of this effect in closed-circuit measurements have not been found in the literature. Further research effort, including 3D computer modeling, for understanding this magnetic phenomenon is underway and will be reported later. 相似文献
28.
29.
A case report of trismus after a dental procedure is evaluated by MR imaging. The medial and lateral pterygoid muscles showed inflammatory changes. Etiologies of trismus are reviewed. 相似文献
30.
N-Fluorosulfuryltrifluoroacetimide and N-chlorosulfuryltrifluoroacetimide have been prepared in high yield by a one-step reaction of trifluorothiolacetic acid with the corresponding fluoro- and chlorosulfuryl isocyanates. The trifluoroacetimides are easily purified by vacuum sublimation from the crude product mixture. 相似文献