全文获取类型
收费全文 | 87篇 |
免费 | 3篇 |
国内免费 | 17篇 |
专业分类
化学 | 58篇 |
晶体学 | 5篇 |
力学 | 5篇 |
综合类 | 2篇 |
数学 | 10篇 |
物理学 | 27篇 |
出版年
2022年 | 4篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2012年 | 12篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2009年 | 7篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有107条查询结果,搜索用时 31 毫秒
31.
In this paper we study radial symmetry and monotonicity of positive solutions of an integral equation arising from some higher-order semilinear elliptic equations in the whole space Rn. Instead of the usual method of moving planes, we use a new Hardy-Littlewood-Sobolev (HLS) type inequality for the Bessel potentials to establish the radial symmetry and monotonicity results. 相似文献
32.
Geng Leng Guibin Lui Yong Chen Hui Yin Dezhong Dan 《Journal of separation science》2012,35(20):2796-2804
A simple, rapid, and efficient method, vortex‐assisted extraction followed by dispersive liquid–liquid microextraction (DLLME) has been developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) in sediment samples prior to analysis by high performance liquid chromatography fluorescence detection. Acetonitrile was used as collecting solvent for the extraction of PAHs from sediment by vortex‐assisted extraction. In DLLME, PAHs were rapidly transferred from acetonitrile to dichloromethane. Under the optimum conditions, the method yields a linear calibration curve in the concentration range from 10 to 2100 ng g?1 for fluorene, anthracene, chrysene, benzo[k]fluoranthene, and benzo[a]pyrene, and 20 to 2100 ng g?1 for other target analytes. Coefficients of determinations ranged from 0.9986 to 0.9994. The limits of detection, based on signal‐to‐noise ratio of three, ranged from 2.3 to 6.8 ng g?1. Reproducibility and recoveries was assessed by extracting a series of six independent sediment samples, which were spiked with different concentration levels. Finally, the proposed method was successfully applied in analyses of real nature sediment samples. The proposed method extended and improved the application of DLLME to solid samples, which greatly shorten the extraction time and simplified the extraction process. 相似文献
33.
Kai Ge Dezhong Liu Kang Chen Lihua Nie Shouzhuo Yao 《Analytical and bioanalytical chemistry》1996,354(1):118-121
A new kind of surface acoustic wave (SAW) enzyme sensor system has been applied to the assay of extracted lipase activity
based on triacetin solution as substrate. A linear relationship between the frequency change and the enzyme activity up to
500 U/L has been obtained, and the detection limit has been evaluated to 0.3 U/L. Kinetic parameters of the extracted lipase
as well as that of the standard enzyme have been estimated. The effects of temperature, pH value and surfactants have been
investigated. A comparison between SAW sensor system and the conductometric method has been carried out. The technique has
been applied to the determination of lipase activity in serum samples.
Received: 17 January 1995 / Revised: 9 March 1995 / Accepted: 16 March 1995
Correspondence to: Shouzhuo Yao 相似文献
34.
Dezhong Chen 《Annals of Global Analysis and Geometry》2011,40(3):339-377
We construct Einstein metrics of non-positive scalar curvature on certain solid torus bundles over a Fano Kähler–Einstein manifold. We show, among other things, that the negative Einstein metrics are conformally compact, and the Ricci-flat metrics have slower-than-Euclidean volume growth and quadratic curvature decay. Also we construct positive Einstein metrics on certain 3-sphere bundles over a Fano Kähler–Einstein manifold. We classify the homeomorphism and diffeomorphism types of the total spaces when the base is the complex projective plane. 相似文献
35.
Mingliang Ma Qiuyu Zhang Jinbo Dou Hepeng Zhang Wangchang Geng Dezhong Yin Shaojie Chen 《Colloid and polymer science》2012,290(12):1207-1213
One-dimensional (ID) magnetic thermosensitive Fe3O4/poly(N-isopropylacrylamide–N,N′-methylenebisacrylamide) (P(NIPAM-MBA)) peapod-like nanochains have been successfully synthesized by magnetic-field-induced precipitation polymerization using Fe3O4 as building blocks and P(NIPAM-MBA) as linker. Fe3O4 microspheres can be arranged with the direction of an external magnetic field in a line via the dipolar interaction between Fe3O4 microspheres and linked permanently via P(NIPAM-MBA) coating during precipitation polymerization. 1D magnetic Fe3O4/P(NIPAM-MBA) peapod-like nanochains can be oriented and aligned along the direction of the external magnetic field. More interestingly, Fe3O4 microspheres in each peapod were regularly arranged in a line and periodically separated through the P(NIPAM-MBA) layers with a visible interparticle spacing. 相似文献
36.
确立了某类分块矩阵[M(11) M12 XM21 Y M23Z M32 M33]的最大秩公式,其中,X,Y和Z是三个受限于四元数线性矩阵方程A1X=C1,XB1=C2,A2Y=D1,YB2=D2,A3Z=E1,ZB3=E2的变量矩阵.作为该公式的一项应用,我们推导出上述矩阵方程解集等同于某类四元数三次矩阵方程组A1X=C1,XB1=C2,A2Y=D1,YB2=D2,A3Z=E1,ZB3=E2,XYZ=J解集的条件. 相似文献
37.
Lilin Zhou Weizhong Yuan Sizhu Wu Dezhong Shen 《Journal of magnetism and magnetic materials》2009,321(18):2799-2804
The synthesis of magnetite nanoparticles coated with pH-sensitive poly((2-dimethylamino) ethyl methacrylate) (PDMAEMA) via atom transfer radical polymerization (ATRP) for use as novel potential carriers for targeted drug delivery and controllable release is reported. The organic/inorganic hybrid nanoparticles were obtained with a narrow molecular weight distribution. The pH-sensitivity of the nanoparticles was investigated by the measurement of the pH dependence of hydrodynamic radius and the superparamagnetism was illustrated by vibrating sample magnetometer (VSM). The behavior of model drug phenolphthalein released from the nanoparticles indicated that the rate of drug release could be effectively controlled by altering the pH values of the environment. 相似文献
38.
Dezhong Shen Guangqiu Shen Xiaoqing Wang Xiaoyang Wang 《Optics & Laser Technology》2002,34(4):277-281
The ordinary method to cut two light pass surfaces of an optical device in Brewster angle parallelly cannot reduce the harmonic's reflective losses of a laser frequency doubler. Right cut method with two unparallel light pass surfaces of Brewster angle of a laser frequency doubler, and preliminary experiment to demonstrate the usefulness of the technique are given. 相似文献
39.
40.