全文获取类型
收费全文 | 156篇 |
免费 | 8篇 |
国内免费 | 3篇 |
专业分类
化学 | 81篇 |
晶体学 | 3篇 |
力学 | 19篇 |
数学 | 6篇 |
物理学 | 58篇 |
出版年
2022年 | 6篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 10篇 |
2012年 | 22篇 |
2011年 | 25篇 |
2010年 | 11篇 |
2009年 | 7篇 |
2008年 | 7篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1902年 | 1篇 |
排序方式: 共有167条查询结果,搜索用时 15 毫秒
1.
The viscosities of seven n-alkylamines from n-butylamine to n-decylamine were determined from 15 to 80°C at 5°C intervals. The intrinsic volumes were determined by extrapolation of the plot of fluidity against molar volume to zero fluidity and found to be a linear function of the number of carbon atoms. Plots of the logarithm of viscosity vs. reciprocal absolute temperature were almost linear. The energies of activation for viscous flow for the n-alkylamines were calculated and found to increase with increase in the carbon number. The B values, based on Hildebrand's equation and representing a measure of a molecules resistance to transport of momentum, were calculated for each of the n-alkylamines. A modified form of the equation describing the change fluidity with temperature was then formulated. It is suggested that the activation energy for viscous flow consists of the sum of the energy required for the expansion of the void volume and the energy required to overcome intermolecular interactions. These energies were calculated and discussed. 相似文献
2.
3.
Yun Khoon Liew Vasanthakumari Neela Rukman Awang Hamat Syafinaz Amin Nordin Pei Pei Chong 《Electrophoresis》2013,34(3):397-400
The typical concentration of protein loaded varies from 0.13 to 1.40 μg/μL for a classical silver staining method in 2DE gel. Here, we present a simple modified classical silver staining method by modifying the silver impregnation and development reaction steps. This modified method detects the protein spots at extremely low loaded concentrations, ranging from 0.0048 to 0.0480 μg/μL. We recommend this modified silver staining as an excellent method for the limited biological samples used for silver‐stained 2DE analysis. Altogether, the protocol takes close to two days from first dimension separation to second dimension separation, followed by silver staining, scanning, and analysis. 相似文献
4.
In the last decade,the functionally graded carbon nanotube reinforced composites(FG-CNTRCs)have attracted considerable interest due to their excellent mechanical properties,and the structures made of FG-CNTRCs have found broad potential applications in aerospace,civil and ocean engineering,automotive industry,and smart structures.Here we review the literature regarding the mechanical analysis of bulk CNTR nanocomposites and FG-CNTRC structures,aiming to provide a clear picture of the mechanical modeling and properties of FG-CNTRCs as well as their composite structures.The review is organized as follows:(1)a brief introduction to the functionally graded materials(FGM),CNTRCs and FG-CNTRCs;(2)a literature review of the mechanical modeling methodologies and properties of bulk CNTRCs;(3)a detailed discussion on the mechanical behaviors of FG-CNTRCs;and(4)conclusions together with a suggestion of future research trends. 相似文献
5.
6.
Y.Z. Peng W.D. Song C.W. An J.J. Qiu J.F. Chong B.C. Lim M.H. Hong T. Liew T.C. Chong 《Applied Physics A: Materials Science & Processing》2005,81(3):565-568
Diluted magnetic semiconductor Co-doped ZnO film has been synthesized by a dual beam pulsed laser deposition method. The magnetic, electrical, and optical properties of the Zn0.985Co0.015O0.67 film are studied in this paper. The film shows ferromagnetic behavior with a coercivity of about 300 Oe at room temperature, and semiconductor behavior with carrier concentration of 2.2×1018 cm-3, and a resistivity of 102 mcm. Structural investigations indicated that the film has similar lattice constants to that of ZnO. It is shown that the film exhibits excellent optical properties with a band gap energy of 3.31 eV, which is close to that of ZnO. The origins of the magnetism are also discussed. PACS 81.15.Fg; 75.50 Pp; 61.72.Vv 相似文献
7.
Hydrogen bonding and dipole moment of water at supercritical conditions: a first-principles molecular dynamics study 总被引:2,自引:0,他引:2
We present a first-principles molecular dynamics study of water near and above the critical point ( T = 647 K, rho = 0.32 g/cm(3)). We find that the systems undergo fast dynamics with continuous formation and breaking of H bonds. At low density, the system fragments mostly into trimers, dimers, and single molecules. At a higher density, more complex structures appear and an extended, albeit very dynamical, H-bond network can be identified. These structures have important consequences for the screening properties of the system. This offers a clue to understanding the peculiar chemical behavior of a supercritical system and allows thermodynamical tuning of its solvent properties. 相似文献
8.
9.
The interaction between an elliptical crack and a spherical inhomogeneity embedded in a three-dimensional solid subject to uniaxial tension is investigated. Both the inhomogeneity and the solid are isotropic but have different elastic moduli. The Eshelby's equivalent inclusion method is applied together with the principle of superposition. An approximate solution for the stress intensity factor is obtained by an approach that expands the distance between the center of the crack and inhomogeneity in series. The local stress field can be increased or decreased depending on the relative modulus of the spherical inhomogeneity and matrix. If the inhomogeneity modulus is larger than that of the matrix, a reduction in the stress intensity factor prevails. Displayed numerically are results to exhibit the influence of inhomogeneity and its distance to the crack. 相似文献
10.
Chin Yee Liew Xiao Hua Ma Chun Wei Yap 《Journal of computer-aided molecular design》2010,24(2):131-141
Phosphoinositide 3-kinases (PI3Ks) inhibitors have treatment potential for cancer, diabetes, cardiovascular disease, chronic
inflammation and asthma. A consensus model consisting of three base classifiers (AODE, kNN, and SVM) trained with 1,283 positive compounds (PI3K inhibitors), 16 negative compounds (PI3K non-inhibitors) and 64,078
generated putative negatives was developed for predicting compounds with PI3K inhibitory activity of IC50 ≤ 10 μM. The consensus model has an estimated false positive rate of 0.75%. Nine novel potential inhibitors were identified
using the consensus model and several of these contain structural features that are consistent with those found to be important
for PI3K inhibitory activities. An advantage of the current model is that it does not require knowledge of 3D structural information
of the various PI3K isoforms, which is not readily available for all isoforms. 相似文献