全文获取类型
收费全文 | 144篇 |
免费 | 6篇 |
专业分类
化学 | 104篇 |
力学 | 4篇 |
数学 | 11篇 |
物理学 | 31篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2017年 | 2篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 8篇 |
2012年 | 5篇 |
2011年 | 10篇 |
2010年 | 9篇 |
2009年 | 9篇 |
2008年 | 11篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2005年 | 9篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1985年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1969年 | 1篇 |
1964年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有150条查询结果,搜索用时 15 毫秒
51.
52.
Nath K Agarwal M Ramola M Husain M Prasad KN Rathore RK Pandey CM Gupta RK 《Magnetic resonance imaging》2009,27(2):198-206
The purpose of this study was to determine whether proton magnetic resonance spectroscopy (PMRS) and diffusion tensor imaging (DTI) indices, fractional anisotropy (FA) and mean diffusivity (MD) can be used to distinguish brain abscess from cystic brain tumors, which are difficult to distinguish by conventional magnetic resonance imaging (MRI). Fifty-three patients with intracranial cystic mass lesions and 10 normal controls were studied. Conventional MRI, PMRS and DTI of all the patients were performed on a 1.5-T GE scanner. Forty patients were with brain abscess and 13 with cystic tumors. Cytosolic amino acids (AAs) were present in 32 of 40 brain abscess patients. Out of 13 patients with cystic tumors, lactate and choline were seen in 3 and only lactate was present in 10 patients on PMRS. All 40 cases of abscess had high FA, while all 13 cases of tumor cysts had high MD values. We conclude that FA measurements are more sensitive in predicting the abscess, while PMRS and MD are more specific in differentiating abscess from cystic tumors. We suggest that PMRS should be combined with DTI rather than with diffusion-weighted imaging as FA can be used as an additional parameter for separation of abscess from other cystic intracranial mass lesions. 相似文献
53.
54.
S M Mazhar 《Proceedings Mathematical Sciences》1991,101(2):121-125
This paper deals with the integrability of a power series. Our results generalize certain results of Ram, and Askey and Karlin. 相似文献
55.
56.
S. M. Mazhar 《Annali di Matematica Pura ed Applicata》1962,59(1):11-25
Summary In this paper, the author proves a theorem on the absoluteCesàro summability of factoredFourier series. His theorem extends a theorem ofMatsumoto and generalizes a theorem ofPrasad andBhatt. 相似文献
57.
Muhammad Shahid Muhammad Mazhar Mazhar Hamid Paul O' Brien Mohammad A. Malik Madeleine Helliwell 《应用有机金属化学》2010,24(10):714-720
Crystalline copper films were deposited by aerosol‐assisted chemical vapor deposition (AACVD) in the absence of hydrogen from two newly synthesized complexes [Cu(deae)(TFA)]4·1.25THF ( 1 ) and [Cu4(OAc)6(bdmap)2(H2O)2]·4H2O ( 2 ) [deae = N, N‐diethylaminoethanolate, TFA = trifloroacetate, OAc = acetate and bdmap = 1,3‐bis(dimethylamino)‐2‐propanolato]. These precursors were prepared in high yield using mixed ligands and crystallized in tetragonal and triclinic crystal systems with space groups 141/a and P ? 1. Complexes 1 and 2 thermally decomposed at 290 and 250 °C, respectively, to yield copper films which were characterized by SEM/EDX for their morphology and composition and PXRD for their crystallinity and phase. These films have smooth morphologies with particle sizes within the range of 0.3–0.6 µm and may find applications in fabrication of ultralarge‐scale integrated circuits. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
58.
Sumaira Ashraf Saif-ur-Rehman Falak Sher Zafar Mahmood Khalid Mazhar Mehmood Irshad Hussain 《Cellulose (London, England)》2014,21(1):395-405
Deposition of nanoparticles on the surface of a variety of materials is a subject of great interest due to their potential applications in electronic devices, sensing, catalysis and bio-medical sciences. In this context, we have explored and compared various methodologies to generate gold and silver nanoparticles on the surface of cellulose fibers. It was found that boiling of the cellulose fibers in alkaline solution of gold and silver salts led to the formation and immobilization of gold and silver nanoparticles. However, in case of lecithin treated and thiol-modified cellulose fibers, high temperature was not essentially required for the formation and deposition of nanoparticles on cellulose substrate. In both these cases, fairly uniform metal nanoparticles were obtained in good yields (~43 wt% gold loading in case of thiol modified cellulose fibers) at room temperature. Borohydride-reduction method resulted in relatively lower loading (~22 wt%) with a wide size distribution of gold and silver nanoparticles on cellulose fibers. All these nanoparticle–cellulose composites were thoroughly characterized using scanning electron microscopy, energy dispersive X-ray, Fourier transform infrared spectroscopy, UV–visible spectroscopy, and elemental analyzer. Thiol modified cellulose–gold nanoparticle composites served as active catalysts in the reduction of 4-nitrophenol into 4-aminophenol. 相似文献
59.
Some new bimetallic carboxylates of tin and germanium with general formula where R1 = m-CH3C6H4, p-CH3C6H4, C6H5, R2 = o-CH3C6H4, p-CH3C6H4, o-CH3OC6H4, C6H5, CH3, have been prepared by the condensation reaction of diethyltin oxide and triarygermyl(substituted)propanoic acid in 1:2 mole ratio, respectively, and characterized by multinuclear (1H, 13C, 119Sn) NMR, 119mSn Mössbauer and IR spectroscopy. The X-ray crystal structure of the ligand I4 [(C6H5)3GeCH(o-CH3OC6H4)CH2COOH] delineate four coordinated germanium atom with a peculiarity of having a molecule of solvent (CHCl3). The chiral center in the synthesized compounds was identified on the basis of 1H NMR data and measurements of angle of rotations. 相似文献
60.
Shabana Taj Din Muhammad M. Ashraf Chaudhry Muhammad Mazhar 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):79-88
Potassium iron(III) hexacyanoferrate(II) supported on poly methyl methacrylate, has been developed and investigated for the
removal of lithium, rubidium and cesium ions. The material is capable of sorbing maximum quantities of these ions from 5.0,
2.5 and 4.5 M HNO3 solutions respectively. Sorption studies, conducted individually for each metal ion, under optimized conditions, demonstrated
that it was predominantly physisorption in the case of lithium ion while shifting to chemisorption with increasing ionic size.
Distribution coefficient (K
d) values followed the order Cs+ > Rb+ > Li+ at low concentrations of metal ions. Following these findings Cs+ can preferably be removed from 1.5 to 5 M HNO3 nuclear waste solutions. 相似文献