全文获取类型
收费全文 | 85篇 |
免费 | 6篇 |
专业分类
化学 | 69篇 |
晶体学 | 1篇 |
力学 | 1篇 |
数学 | 8篇 |
物理学 | 12篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 6篇 |
2012年 | 5篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2008年 | 11篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1997年 | 1篇 |
1990年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1970年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有91条查询结果,搜索用时 15 毫秒
1.
Clowers BH Dwivedi P Steiner WE Hill HH Bendiak B 《Journal of the American Society for Mass Spectrometry》2005,16(5):660-669
A series of isobaric disaccharide-alditols, four derived from O-linked glycoproteins, and select trisaccharides were rapidly resolved using tandem high resolution atmospheric pressure ion-mobility time-of-flight mass spectrometry. Electrospray ionization was used to create the gas-phase sodium adducts of each carbohydrate. Using this technique it was possible to separate up to three isobaric disaccharide alditols and three trisaccharides in the gas phase. Reduced mobility values and experimentally determined ion-neutral cross sections are reported for each sodium-carbohydrate complex. These studies demonstrated that ion mobility separations at atmospheric pressure can provide a high-resolution dimension for analysis of carbohydrate ions that is complementary to traditional mass spectral (m/z) ion analysis. Combining these independent principles for separation of ions provides a powerful new bioanalytical tool for the identification of isomeric carbohydrates. 相似文献
2.
Valency is defined for each molecular orbital. The molecular orbital valency values are shown to be a good measure of the bonding nature of the molecular orbital. Comparisons are made with photoelectron spectral studies and Mulliken overlap population analysis.The variation of molecular valency and molecular orbital valency with bond angle is studied. It is found that for all the molecules presently considered, energy is linearly related to valency and that the molecular valency reaches a maximum at the equilibrium bond angle. It is also shown that the molecular orbital valency can serve as a quantitatively reliable ordinate for Mulliken-Walsh diagrams. 相似文献
3.
4.
The reaction of 4-chloro-2-methylquinolines and 1-naphthylamine under neat conditions yielded 2-methyl-N-(1-naphthyl)quinolin-4-amines. These potential intermediates on reaction with aliphatic and aromatic carboxylic acids yielded the respective 7-alkyl and -aryl substituted benzo[h]naphtho[1,2-b][1,6]naphthyridines. The highly deshielded protons in the final compounds were assigned on the basis of 2D NMR studies. 相似文献
5.
Priyadarsini Sreenivasan Jijo Wilson Prabha Damodaran Nair Lynda Velutheril Thomas 《先进技术聚合物》2020,31(5):1139-1149
This work reports a novel fabrication technique for development of channels on paper‐based microfluidic devices using the syringe module of a 3D printing syringe–based system. In this study, printing using polycaprolactone (PCL)‐based ink (Mw 70 000‐90 000) was employed for the generation of functional hydrophobic barriers on Whatman qualitative filter paper grade 1 (approximate thickness of 180 μm and pore diameter of 11 μm), which would effectively channelize fluid flow to multiple assay zones dedicated for different analyte detection on a microfluidic paper‐based analytical device (μPAD). The standardization studies reveal that a functional hydrophilic channel for sample conduction fabricated using the reported technique can be as narrow as 460.7 ± 20 μm and a functional hydrophobic barrier can be of any width with a lower limit of about 982.2 ± 142.75 μm when a minimum number of two layers of the ink is extruded onto paper. A comparison with the hydrodynamic model established for writing with ink is used to explain the width of the line printed by this system. A fluid flow analysis through a single channel system was also carried out to establish its conformity with the Washburn model, which governs the fluid flow in two‐dimensional μPAD. The presented fabrication technique proves to be a robust strategy that effectively taps the advantages of this 3D printing technique in the production of μPADs with enhanced speed and reproducibility. 相似文献
6.
7.
Baker ML Piligkos S Bianchi A Carretta S Collison D McDouall JJ McInnes EJ Mutka H Timco GA Tuna F Vadivelu P Weihe H Güdel HU Winpenny RE 《Dalton transactions (Cambridge, England : 2003)》2011,40(34):8533-8539
An investigation into the physical consequences of including a Jahn-Teller distorted Cu(II) ion within an antiferromagnetically coupled ring, [R(2)NH(2)][Cr(7)CuF(8)((O(2)C(t)Bu)(16))] is reported. Inelastic neutron scattering (INS) and electron paramagnetic resonance (EPR) spectroscopic data are simulated using a microscopic spin Hamiltonian, and show that the two Cr-Cu exchange interactions must be inequivalent. One Cr-Cu exchange is found to be antiferromagnetic and the other ferromagnetic. The geometry of the Jahn-Teller elongation is deduced from these results, and shows that a Jahn-Teller elongation axis must lie in the plane of the Cr(7)Cu wheel; the elongation is not observed by X-ray crystallography, due to positional disorder of the Cu site within the wheel. An electronic structure calculation confirms the structural distortion of the Cu site. 相似文献
8.
Prabha D. Nair M. Jayabalan V. N. Krishnamurthy 《Journal of polymer science. Part A, Polymer chemistry》1990,28(13):3775-3786
Hydrophobic-hydrophilic interpenetrating polymer networks (IPNs) of polyurethane and polyacrylamide have been synthesized. The IPNs have been characterized by IR, thermal, and mechanical studies. SEM studies indicate phase mixing of some IPNs. Solvent resistance and surface hydrophilicity as evidenced by contact angle measurements suggest that these IPNs could be used for biomedical applications. 相似文献
9.
The nature of the interaction between the unsaturated monomer and the chelate, Fe(DPM)3, is studied in detail. The interaction is found to occur only in solution. The stoichiometry of interaction and the equilibrium constant are evaluated. With the help of spectral evidence, attempts are made to point out the specific sites of interaction. 相似文献
10.