全文获取类型
收费全文 | 178篇 |
免费 | 17篇 |
国内免费 | 29篇 |
专业分类
化学 | 126篇 |
晶体学 | 4篇 |
力学 | 2篇 |
综合类 | 1篇 |
数学 | 44篇 |
物理学 | 47篇 |
出版年
2024年 | 2篇 |
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 12篇 |
2014年 | 9篇 |
2013年 | 10篇 |
2012年 | 10篇 |
2011年 | 16篇 |
2010年 | 13篇 |
2009年 | 10篇 |
2008年 | 12篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2001年 | 7篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有224条查询结果,搜索用时 15 毫秒
121.
122.
123.
Cahn-Hilliard vs Singular Cahn-Hilliard equations in simulations of immiscible binary fluids 下载免费PDF全文
Lizhen Chen 《Journal of Applied Analysis & Computation》2018,8(4):1050-1060
An efficient semi-implicit spectral method is implemented to solve the Cahn-Hilliard equation with a variable mobility in this paper. We compared the kinetics of bulk-diffusion-dominated and interface-diffusion-dominated coarsening in two-phase systems. As expected, the interface-diffusion-controlled coarsening evolves much slower. Also we find that the velocity field will be caused different greatly by using Singular Cahn-Hilliard equation and using Cahn-Hilliard in the simulation of immiscible binary fluids. 相似文献
124.
A high-nuclear {Co16-V4} cluster was firstly isolated by pure inorganic lacunary POM units, which exhibits excellent photocatalytic activity for CO2-to-CO conversion under visible light irradiation. 相似文献
125.
Differential Effects of Polymer‐Surface Decoration on Drug Delivery,Cellular Retention,and Action Mechanisms of Functionalized Mesoporous Silica Nanoparticles 下载免费PDF全文
Polymer‐surface decoration has been found to be an effective strategy to enhance the biological activities of nanomedicine. Herein, three different types of polymers with a cancer‐targeting ligand Arg‐Gly‐Asp peptide (RGD) have been used to decorate mesoporous silica nanoparticles (MSNs) and the functionalized nanosystems were used as drug carriers of oxaliplatin (OXA). The results showed that polymer‐surface decoration of the MSNs nanosystem by poly(ethylene glycol) (PEG) and polyethyleneimine (PEI) significantly enhanced the anticancer efficacy of OXA, which was much higher than that of chitosan (CTS). This effect was closely related to the enhancement of the cellular uptake and cellular drug retention. Moreover, PEI@MSNs‐OXA possessed excellent advantages in penetrating ability and inhibitory effects on SW480 spheroids that were used to simulate the in vivo tumor environments. Therefore, this study provides useful information for the rational design of a cancer‐targeted MSNs nanosystem with polymer‐surface decoration. 相似文献
126.
This paper reports the growth and spectral properties of 3.5 at% Nd3+:LaVO4 crystal with diameter of 20×15 mm2 which has been grown by the Czochralski method. The spectral parameters were calculated based on Judd–Ofelt theory. The intensity parameters Ωλ are: Ω2=2.102×10−20 cm2, Ω4=3.871×10−20 cm2, Ω6=3.235×10−20 cm2. The radiative lifetime τr is 209 μs and calculated fluorescence branch ratios are: β1(0.88μm)=45.2, β2(1.06μm)=46.7, β3(1.34μm)=8.1. The measured fluorescence lifetime τf is 137 μm and the quantum efficiency η is 65.6%. The absorption band at 808 nm wavelength has an FWHM of 20 nm. The absorption and emission cross sections are 3×10−20 and 6.13×10−20 cm2, respectively. 相似文献
127.
128.
Plasma-polymerization of octafluorocyclobutane was carried out in a capacitively coupled tubu-lar reactor with external electrodes. The number-average molecular weight, melting temperature,decomposition temperature and solubility in te trafluorodibromoethane of the products was mea-sured and the polymer structure was characterized by ESR. IR and ~(1)9F-NMR methods. The experi-mental results show the absence of the highly crosslinked structure but a fluorine-deficient structurecaused by free-radicals, carbonyl groups. double bonds and multicage-like segments in the polymer. 相似文献
129.
关于Tl(Ⅲ)电极的研制已有文献[1-3]报导,但尚未见应用实例。本文在文献[3]液膜T1Br4-电极的基础上,改变条件研制了PVC膜TlBr4-电极,其稳定性、选择性和重现性有了较大提高,使电极更具有实用价值,以本电极为指示电极对TlBr4-乙基紫或丁基罗丹明B体系获得了良好的电位滴定曲线;应用本电极按改进的零点电位法拟定了适宜于测定烟灰中微量鈍的操作步骤,分析了实际样品,与光度法对照,相对误差小于10%。 相似文献
130.
局部可分度量空间的序列覆盖s象 总被引:10,自引:0,他引:10
本文给出了局部可分度量空间的1序列覆盖s象,2序列覆盖s象,强序列覆盖s象,序列覆盖s象及子序列覆盖s象的内在刻划.从而使关于对度量空间的各类s象的内在刻划方面的研究更趋于完整. 相似文献