全文获取类型
收费全文 | 154篇 |
免费 | 5篇 |
专业分类
化学 | 112篇 |
力学 | 3篇 |
数学 | 8篇 |
物理学 | 36篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 11篇 |
2013年 | 11篇 |
2012年 | 8篇 |
2011年 | 9篇 |
2010年 | 7篇 |
2009年 | 3篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 23篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 8篇 |
2002年 | 2篇 |
2001年 | 1篇 |
1998年 | 4篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1978年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有159条查询结果,搜索用时 15 毫秒
41.
JPC – Journal of Planar Chromatography – Modern TLC - A robust and eco-friendly stability-indicating high-performance thin-layer chromatography (HPTLC) method was developed for the... 相似文献
42.
Shailesh S. Dixit 《Tetrahedron》2008,64(9):2160-2171
The binding constants of crown ethers prepared from tetra-O-substituted myo- and scyllo-inositol derivatives and 2-O-substituted myo- and scyllo-inositol-1,3,5-orthoformates, with metal picrates show that the O-substituents and the relative orientation of the crown ether oxygen atoms contribute significantly to the binding of crown ethers with metal ions. In particular, the binding efficiency of myo-inositol derived crown ethers to silver and potassium ions could be enhanced by introducing benzyl ethers in the inositol ring. Hence binding efficacy and selectivity of metal ions to inositol derived crown ethers can be tuned by varying substituents on the myo-inositol ring and/or the relative orientation of crown ether oxygen atoms. 相似文献
43.
Peter Dierkes Shailesh Ramdeehul Laurent Barloy Andre De Cian Jean Fischer Paul C. J. Kamer Piet W. N. M van Leeuwen John A. Osborn 《Angewandte Chemie (International ed. in English)》1998,37(22):3116-3118
Palladium complexes of the chiral diphosphanes 1 and 2 which possess a rigid backbone and a large bite angle catalyze the alkylation of allyl compounds with both high enantioselectivities and reaction rates, particularly with less sterically demanding substrates. 1 : R=Me, X=S; 2 : R=H, X=C(CH3)2. 相似文献
44.
45.
Eugenia Pechkova Shailesh Tripathi Claudio Nicolini 《Journal of synchrotron radiation》2009,16(3):330-335
The grazing‐incidence small‐angle X‐ray scattering technique has been used here with a microfocus beamline (µGISAXS) to study the effect of temperature on the protein reorganization taking place in a Langmuir–Schaefer multilayered enzyme film. The study appears quite reproducible in the two enzymes being utilized, penicillin G acylase and urease. In‐plane and out‐of‐plane cuts are used to account for the changes in the film thickness and distance between structures taking place by the process of heating up to 423 K and cooling to room‐temperature. The out‐of‐plane cut suggests that the structures are getting closer and are becoming more organized owing to the heating affect. Merging of layers is likely to occur during the heating and cooling process, leading to a loss of correlation between the interfaces of the layers and to the establishment of long‐range order. The dramatic increase in long‐range order in the Langmuir–Blodgett multilayered enzyme films after heating and cooling, made here apparent by grazing‐incidence small‐angle X‐ray scattering using a microbeam, could in the future open the way to avoiding the bottleneck of protein crystallization for protein structure determination. 相似文献
46.
Bhanubhai N Suhagia Shailesh A Shah Ishwarsinh S Rathod Haresh M Patel Dinesh R Shah Bhavin P Marolia 《Analytical sciences》2006,22(5):743-745
A simple and sensitive high-performance thin-layer chromatography (HPTLC) method has been developed for the quantitative estimation of gatifloxacin and ornidazole in its combined dosage forms. Gatifloxacin and ornidazole were chromatographed on silica Gel 60 F(254) TLC plate using n-butanol:methanol:ammonia (6 M) (8:1:1.5 v/v) as the mobile phase and scanned at 302 nm using a Camag TLC Scanner 3. The R(f) value of gatifloxacin and ornidazole was found to be 0.21 +/- 0.02 and 0.76 +/- 0.04, respectively. The linearity of gatifloxacin and ornidazole were in the range of 100 - 500 ng/spot and 250 - 1250 ng/spot, respectively. The limit of detection was found to be 40 ng/spot for gatifloxacin and 100 ng/spot for ornidazole. The proposed method was applied for the determination of gatifloxacin and ornidazole in combined dosage forms. 相似文献
47.
Sabir H. Mashraqui Tabrez Khan Subramanian Sundaram Shailesh Ghadigaonkar 《Tetrahedron letters》2008,49(23):3739-3743
Phenothiazine-pyridyl chalcone, a new internal charge transfer (ICT) probe, has been designed that allows naked eye detection and a reversible, ratiometric ‘on-off’ sensing capability for biologically and environmentally significant Cu2+ in CH3OH-H2O (4:1 v/v) under buffered conditions. The association constants determined using spectrophotometric and the fluorimetric techniques follow the order Cu2+ > Ni2+ > Co2+ > Zn2+ > Cd2+ > Mg2+ ≈ Ba2+ ≈ Ca2+ ≈ K+≈ Na+ ≈ Li+. 相似文献
48.
Surface sensitive probe of the morphological and structural aspects of CdSe core-shell nanoparticles
Himani Sharma Shailesh N. Sharma Ram Kishore S.M. Shivaprasad 《Applied Surface Science》2007,253(12):5325-5333
The promising technological applications of colloids of CdSe nanoparticles in solid state devices is hampered due to issues related to their stoichiometry, agglomeration effects and core-shell relationship. Due to the short inelastic mean free path of core-level electrons, X-ray photoelectron spectroscopy is the most reliable method for analysis at the nanometer depth scale, and in conjunction with layer by layer ion beam erosion it can provide valuable information regarding distribution of elements along the depth of the sample. In this work, we address the issue of synthesis of CdSe nanoparticles and probing them by XPS and conventional techniques such as like transmission electron microscopy (TEM) and X-ray diffraction (XRD). Cd/Se input precursor ratio is varied to form colloidal TOP/TOPO capped CdSe nanoparticles. An optimum input precursor ratio is determined where stoichiometric yield, efficiently capped smallest sized (∼5 nm) CdSe nanoparticles with superior optical, structural and morphological properties are obtained. Electron diffraction and deconvolution of XPS-core-levels enables the identification of the different compositional regimes of CdSe nanocrystallites. For non-optimal precursor ratios, the presence of Cd- and Se-related oxides are observed. This multi-technique approach has enabled us to pictorially model the compositional, structural and morphological aspects of TOP/TOPO capped CdSe nanoparticles. 相似文献
49.
Room-temperature (≈ 300 K) EPR studies of Cu2+-doped in NH4I single crystals are reported. The Cu2+ ion is found to substitute for NH4+ and get associated with a second or fourth neighbour cation vacancy. The spectra for the two distinct types of centres have been analysed and the parameters presented. 相似文献
50.
The paramagnetic resonance of Gd3+ in Sm(NO3)3.6H2O single crystals, grown from solution, is studied at room temperature. A seven line spectrum for H//Z as well as for H//X corresponding to ΔM=±1 transitions are observed. The spin Hamiltonian analysis is presented. 相似文献