全文获取类型
收费全文 | 599篇 |
免费 | 32篇 |
国内免费 | 2篇 |
专业分类
化学 | 394篇 |
晶体学 | 6篇 |
力学 | 20篇 |
数学 | 48篇 |
物理学 | 165篇 |
出版年
2023年 | 5篇 |
2022年 | 14篇 |
2021年 | 16篇 |
2020年 | 12篇 |
2019年 | 18篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 21篇 |
2015年 | 13篇 |
2014年 | 17篇 |
2013年 | 60篇 |
2012年 | 44篇 |
2011年 | 44篇 |
2010年 | 24篇 |
2009年 | 7篇 |
2008年 | 28篇 |
2007年 | 27篇 |
2006年 | 33篇 |
2005年 | 31篇 |
2004年 | 17篇 |
2003年 | 19篇 |
2002年 | 13篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 10篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1979年 | 7篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1972年 | 2篇 |
1930年 | 2篇 |
1927年 | 1篇 |
排序方式: 共有633条查询结果,搜索用时 468 毫秒
81.
The charge transfer from one hemisphere to the other, observed inpp-collisions is explained on the basis of a ‘mixed two component’ model, which has been proposed previously to account for
the multiplicity distribution of charged particles. Results of the calculations, based on the model, for various measurable
quantities relating to charge transfer are compared with the available experimental data. 相似文献
82.
Narayan T. Akinchan Richa Akinchan Douglas X. West YongHong Yang 《Transition Metal Chemistry》1994,19(2):135-140
Summary The preparation and spectral properties of five copper(II) complexes of semicarbazones, derived from 2-hydroxy-naphthaldehyde
(NPSCZ), benzoin (BZSCZ) and isatin (ISSCZ) are described. I.r., electronic, e.s.r. 1H and 13C n.m.r. spectra show that the semicarbazone's coordination is distorted trigonal bipyramidal for [Cu(BZSCZ-2H)(H2O)], distorted tetragonal pyramidal for [Cu(NPSCZ)2](ClO4)2 and dimeric for the other three complexes. 相似文献
83.
Sanjay Pralhadrao Jadhav Bhagwan Ghanshamji Toksh Kamalakar Marutirao Jadhav Narayan Dadarao Shinde 《化学物理学报》2010,23(4):459-464
采用湿化学共沉淀法合成了Ni1-xCdxFe2O4 (0≤x≤0.5)的混合铁氧体,利用X射线衍射对其结构和晶相进行表征.结果表明:随着镉Cd浓度的增加晶格参数逐渐增大.扫描电子显微镜研究微观结构,TG/DTA研究了硫酸共沉淀物.揭示了在650 oC合成铁氧体同时进行分解.测量了纳米粒子的磁化强度和交流磁化率.结果表明,Ni1-xCdxFe2O4混合铁氧体的磁化率、居里温度和有效磁矩随着镉含量的增加下降。 相似文献
84.
Markad SD Karanjule NS Sharma T Sabharwal SG Dhavale DD 《Organic & biomolecular chemistry》2006,4(19):3675-3680
The Johnson-Claisen rearrangement of D-gluco and L-ido-derived allylic orthoesters afforded gamma,delta-unsaturated ester that on ester reduction, epoxidation, regioselective oxirane opening by sodium azide and hydrogenation led to sugar amino alcohols--immediate precursors for 1-deoxy-homonojirimycin 3a,b, and polyhydroxylated homoazepanes 4a,b. Our synthetic approach and glycosidase inhibitory activity is reported. 相似文献
85.
Spectroscopic identification of S-Au interaction in cysteine capped gold nanoparticles 总被引:1,自引:0,他引:1
Aryal S B K C R Dharmaraj N Bhattarai N Kim CH Kim HY 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,63(1):160-163
This study deals with the synthesis of cysteine capped gold nanoparticles with an average size of 12 nm by borohydride reduction and spectroscopic identification of SAu interaction. We have studied the interaction of thiol with gold nanoparticles in aqueous medium by employing UV-vis, Raman, NMR, and FT-IR spectroscopy. The shifting of gold plasmon resonance in the UV-vis spectra shows the stabilization of gold nanoparticles by cysteine. The disappearance of S-H stretching in both the IR and Raman spectra and the shifting of the NMR signals of the protons in close proximity to the metal center supported the existence of the S-Au interaction in cysteine capped gold nanoparticles. The TEM images shows cysteine capped gold nanoparticles as distinct and spherical entities as compared to free colloidal gold nanoparticles. 相似文献
86.
87.
O. Prasad L. Sinha N. Misra V. Narayan N. Kumar A. Kumar 《Journal of Applied Spectroscopy》2010,77(4):468-478
The present work deals with the structural, electronic, and vibrational analysis of rivastigmine. Rivastigmine, an antidementia
medicament, is credited with significant therapeutic effects on the cognitive, functional, and behavioural problems that are
commonly associated with Alzheimer’s dementia. For rivastigmine, a number of minimum energy conformations are possible. The
geometry of twelve possible conformers has been analyzed and the most stable conformer was further optimized at a higher basis
set. The electronic properties and vibrational frequencies were then calculated using a density functional theory at the B3LYP
level with the 6-311+G(d, p) basis set. The different molecular surfaces have also been drawn to understand the activity of
the molecule. A narrower frontier orbital energy gap in rivastigmine makes it softer and more reactive than water and dimethylfuran.
The calculated value of the dipole moment is 2.58 debye. 相似文献
88.
Fixed point theorems for generalized weakly S-contractive mappings in partial metric spaces
下载免费PDF全文
![点击此处可从《Journal of Applied Analysis & Computation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Lakshmi Narayan Mishr Shiv Kant Tiwari Vishnu Narayan Mishra 《Journal of Applied Analysis & Computation》2015,5(4):600-612
In this paper, we establish some unique xed point theorems for generalized weakly S-contractive with nondecreasing and weakly increasing mappings in complete partial metric space. Also, we give some examples for strengthens of our main results. 相似文献
89.
90.
The present paper deals with quantization of perfect fluid anisotropic cosmological models. Bianchi type V and IX models are discussed following Schutz’s method of expressing fluid velocities in terms of six potentials. The wave functions are found for several examples of equations of state. In one case a complete wave packet could be formed analytically. The initial singularity of a zero proper volume can be avoided in this case, but it is plagued by the usual problem of non-unitarity of anisotropic quantum cosmological models. It is seen that a particular operator ordering alleviates this problem. 相似文献