全文获取类型
收费全文 | 334篇 |
免费 | 13篇 |
国内免费 | 1篇 |
专业分类
化学 | 221篇 |
晶体学 | 1篇 |
力学 | 27篇 |
数学 | 32篇 |
物理学 | 67篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 11篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 5篇 |
2014年 | 17篇 |
2013年 | 20篇 |
2012年 | 28篇 |
2011年 | 34篇 |
2010年 | 8篇 |
2009年 | 17篇 |
2008年 | 17篇 |
2007年 | 14篇 |
2006年 | 13篇 |
2005年 | 22篇 |
2004年 | 14篇 |
2003年 | 13篇 |
2002年 | 9篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有348条查询结果,搜索用时 15 毫秒
281.
Haomin Wang Catherine Choong Jun Zhang Kie Leong Teo Yihong Wu 《Solid State Communications》2008,145(7-8):341-345
Excess conductance fluctuations with peculiar temperature dependence from 1.4 to 250 K were observed in curved nanographite sheets with electrode gap lengths of 300 and 450 nm, whereas the conductance fluctuation is greatly suppressed above 4.2 K when the electrode gap lengths increase to 800 and 1000 nm. The former is discussed in the context of the presence of a small energy bandgap in the nanographite sheets, while the latter is attributed to the crossover from the coherent transport to diffusive transport regime. 相似文献
282.
A. F. T. Leong A. K. Robinson K. Fezzaa T. Sun N. Sinclair D. T. Casem P. K. Lambert C. J. Hustedt N. P. Daphalapurkar K. T. Ramesh T. C. Hufnagel 《Experimental Mechanics》2018,58(9):1423-1437
We demonstrate the use of X-ray phase contrast imaging with sub-microsecond temporal resolution to obtain quantitative visualization of dynamic fracture processes in brittle solids. We examine an amorphous solid (fused silica), a ceramic single crystal (single-crystal quartz), and a polycrystalline ceramic (boron carbide), in the form of single-edge notched specimens loaded using a three-point apparatus at nominal strain rates up to \(\sim \)800 s?1. We observe that the crack tip speed for boron carbide is relatively independent of mode I stress intensity factor rate (\(\dot {K}_{\mathrm {I}}\)) for these rates of loading, while that of fused silica and single-crystal quartz increases with \(\dot {K}_{\mathrm {I}}\). Further, for the amorphous and single crystal cases, we observe the development of a crack tip instability in the form of crack branching as the crack tip speed approaches 45% of the Rayleigh wave speed. This suggests that strain-rate-dependent mechanisms contribute to crack branching. Such mechanisms may, in turn, affect the macroscopic fracture properties of these materials. 相似文献
283.
284.
Modification to the flow field about a finite-span cylinder of low-aspect ratio (AR = 3) by a single synthetic jet, mounted normal to the cylinder axis, was studied experimentally using surface-mounted pressure taps, stereoscopic particle image velocimetry (SPIV), and constant-temperature anemometry. The synthetic jet altered the circulation about the cylinder and created a large spanwise change to the surface pressure, much greater than the dimensions of its orifice. SPIV measurements in the near wake showed that the synthetic jet enhances mixing of the downwash from the cylinder free end with the wake deficit, vectoring and narrowing the wake. The synthetic jet penetrates through the streamwise vorticity, enhancing mixing within the wake and reducing the power associated with the shedding frequency, St = 0.155, except below the vortex dislocation, where the shedding frequency was increased to that corresponding to a quasi-two-dimensional cylinder, St = 0.22. 相似文献
285.
L. H. Tan T. J. Barber S. S. Leong 《International Journal of Computational Fluid Dynamics》2013,27(6):457-473
An experimental and numerical study of thermal Marangoni convection in shallow liquid layers was carried out for a range of temperature differences and layer depths. This was done to permit earth based experiments to be undertaken in situations where Marangoni convection dominated the flow. Particle image velocimetry (PIV) was used to obtain the flow patterns and velocity vectors. The experimental results were compared to numerical models created using FLUENT V6. Both results are in good agreement. The liquid free surface profile due to the presence of the menisci is shown to be critical for good quantitative validation. The layer depths are also proven to be shallow enough for Marangoni convection to dominate over buoyancy under normal gravity conditions. 相似文献
286.
Assessment of three regularization-based and two eddy-viscosity-based subgrid-scale (SGS) turbulence models for large eddy simulations (LES) are carried out in the context of magnetohydrodynamic (MHD) decaying homogeneous turbulence (DHT) with a Taylor scale Reynolds number (Reλ) of 120 and a MHD transition-to-turbulence Taylor-Green vortex (TGV) problems with a Reynolds number of 3000, through direct comparisons to direct numerical simulations (DNS). Simulations are conducted using the low-magnetic Reynolds number approximation (Rem<<1). LES predictions using the regularization-based Leray- α,LANS- α, and Clark- α SGS models, along with the eddy viscosity-based non-dynamic Smagorinsky and the dynamic Smagorinsky models are compared to in-house DNS for DHT and previous results for TGV. With regard to the regularization models, this work represents their first application to MHD turbulence. Analyses of turbulent kinetic energy decay rates, energy spectra, and vorticity fields made between the varying magnetic field cases demonstrated that the regularization models performed poorly compared to the eddy-viscosity models for all MHD cases, but the comparisons improved with increase in magnitude of magnetic field, due to a decrease in the population of SGS eddies within the flow field. 相似文献
287.
Gold nanoclusters are good catalyst precursors for the catalytic dehydrogenation of indolines, tetrahydroquinazolines, and related N-heterocycles. The catalytically active species is presumably Au(0) nanoparticles. 相似文献
288.
Combining both device and particle designs are the essential concepts to be considered in magnetophoretic system development. Researcher efforts are often dedicated to only one of these design aspects and neglecting the interplay between them. Herein, to bring out importance of the idea of integration between device and particle, we reviewed the working principle of magnetophoretic system (includes both device and particle design concepts). Since, the magnetophoretic force is influenced by both field gradient and magnetization volume, hence, accurate prediction of the magnetophoretic force is relying on the availability of information on both parameters. In device design, we focus on the different strategies used to create localized high-field gradient. For particle design, we emphasize on the scaling between hydrodynamic size and magnetization volume. Moreover, we also briefly discussed the importance of magnetoshape anisotropy related to particle design aspect of magnetophoretic systems. Next, we illustrated the need for integration between device and particle design using microscale applications of magnetophoretic systems, include magnetic tweezers and microfluidic systems, as our working example. On the basis of our discussion, we highlighted several promising examples of microscale magnetophoretic systems which greatly utilized the interplay between device and particle design. Further, we concluded the review with several factors that possibly resulted in the lack of research efforts related to device and particle design integration. 相似文献
289.
290.
A Small‐Molecule Probe for Selective Profiling and Imaging of Monoamine Oxidase B Activities in Models of Parkinson’s Disease
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Lin Li Dr. Cheng‐Wu Zhang Dr. Jingyan Ge Linghui Qian Bing‐Han Chai Prof. Dr. Qing Zhu Prof. Dr. Jun‐Seok Lee Prof. Dr. Kah‐Leong Lim Prof. Dr. Shao Q. Yao 《Angewandte Chemie (International ed. in English)》2015,54(37):10821-10825
The design of the first dual‐purpose activity‐based probe of monoamine oxidase B (MAO‐B) is reported. This probe is highly selective towards MAO‐B, even at high MAO‐A expression levels, and could sensitively report endogenous MAO‐B activities by both in situ proteome profiling and live‐cell bioimaging. With a built‐in imaging module as part of the probe design, the probe was able to accomplish what all previously reported MAO‐B imaging probes failed to do thus far: the live‐cell imaging of MAO‐B activities without encountering diffusion problems. 相似文献