全文获取类型
收费全文 | 185篇 |
免费 | 8篇 |
国内免费 | 3篇 |
专业分类
化学 | 155篇 |
晶体学 | 1篇 |
力学 | 5篇 |
数学 | 10篇 |
物理学 | 25篇 |
出版年
2022年 | 3篇 |
2021年 | 13篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 19篇 |
2012年 | 11篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 10篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 17篇 |
2003年 | 14篇 |
2002年 | 9篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1982年 | 1篇 |
1977年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有196条查询结果,搜索用时 31 毫秒
191.
Luminita Andronic Alexandru Enesca Cristina Cazan Maria Visa 《Journal of Sol-Gel Science and Technology》2014,71(3):396-405
Titanium oxide–active carbon composites (TiO2–AC) with photocatalytic activity were prepared by sol–gel method at low temperature. Titanium isopropoxide and active carbon were used as precursors, ethanol as solvent and HNO3 as catalyst. The composition of the studied composites was accomplished by means of X-ray diffraction, and Fourier Transform-Infrared spectrometry. The rutile crystalline phase was present in all samples. In scanning electron microscopy images the TiO2 aggregates existed either on the surface of the active carbon or heterogeneously dispersed over the whole catalyst matrix. The contact angle and point of zero charge measurements were applied to characterise the surface energy and surface charge. The photocatalytic activities of the TiO2–AC composites were evaluated in the bleaching of methyl orange and methylene blue solution from ternary mixture of methyl orange, methylene blue and Triton X100. The double divisor ratio spectra derivative method (as a multivariable calibration method) was developed to overcome the spectral overlapping, for the simultaneous analysis of ternary mixture. 相似文献
192.
Rodica Olar Gina Vasile Scaeteanu Ioana Dorina Vlaicu Luminita Marutescu Mihaela Badea 《Journal of Thermal Analysis and Calorimetry》2014,118(2):1195-1202
Three new coordinative compounds of the type [Co(en)2CO3]·0.75H2O (1) and [M(en)2(H2O)2]CO3 ((2) M:Ni, (3) M:Cu; en: ethylenediamine) were synthesized and characterized. The IR and UV–Vis spectral data indicate that ethylenediamine acts as chelate, while carbonate ions act as bidentate chelate ligand for (1)/counter ion for (2) and (3) generating complexes with octahedral stereochemistry. The thermal behavior provided confirmation of the complexes composition, as well as the number and the nature of water molecules and the intervals of thermal stability. The biological assays revealed a good activity against Enterococcus faecium for copper complex. 相似文献
193.
The reaction of the low-spin iron(III) complex [Fe(dmbpy)(CN)(4)](-) (1) with fully solvated cobalt(II) ions affords the cyanide-bridged heterobimetallic chain {[Fe(III)(dmbpy)(CN)(4)](2)Co(II)(H(2)O)(2)}(n) · 4nH(2)O (2), which exhibits intrachain ferromagnetic coupling and double slow relaxation of the magnetization. 相似文献
194.
Hildebrand A Lönnecke P Silaghi-Dumitrescu L Silaghi-Dumitrescu I Hey-Hawkins E 《Dalton transactions (Cambridge, England : 2003)》2006,(7):967-974
When an excess of nBuLi was used in the ortho-dilithiation of thiophenol or 2-trimethylsilylthiophenol in the presence of TMEDA (TMEDA = N,N,N',N'-tetramethylethylenediamine), deprotonation of TMEDA occurred and crystals of [Li3{(2-S-C6H4)(CH2MeNCH2CH2NMe2)(TMEDA)}]2 (1) or [Li4{(2-S-3-SiMe3-C6H3)(CH2MeNCH2CH2NMe2)2(TMEDA)}] (2) were obtained. Molecular orbital calculations on gas-phase 1 and 2 at the DFT B3LYP/6-31G(d) level reproduce the experimental structures fairly well. In spite of the short Li...Li distances, total electron density representations do not support the existence of Li...Li interactions. 相似文献
195.
Lai WC McLean N Gansmüller A Verhoeven MA Antonioli GC Carravetta M Duma L Bovee-Geurts PH Johannessen OG de Groot HJ Lugtenburg J Emsley L Brown SP Brown RC DeGrip WJ Levitt MH 《Journal of the American Chemical Society》2006,128(12):3878-3879
A new double-quantum solid-state NMR pulse sequence is presented and used to measure one-bond 13C-13C J-couplings in a set of 13C2-labeled rhodopsin isotopomers. The measured J-couplings reveal a perturbation of the electronic structure at the terminus of the conjugated chain but show no evidence for protein-induced electronic perturbation near the C11-C12 isomerization site. This work establishes NMR methodology for measuring accurate 1JCC values in noncrystalline macromolecules and shows that the measured J-couplings may reveal local electronic perturbations of mechanistic significance. 相似文献
196.
J. Auleytner H. Fiedorowicz Z. Furmanik Z. Patron K. Regiski 《Crystal Research and Technology》1992,27(7):959-964
In the experiment a (111) oriented silicon plate was subjected to implantation by 80 keV Ge ions. Then the pulsed-laser annealing of this sample was carried out by using neodymium laser to form several areas irradiated with different light power. The effectiveness of the annealing has been analyzed by means of transmission X-ray topography, double crystal X-ray spectrometry, and reflection high energy electron diffraction. These three methods have appeared to be complementary and very effective in studying the spatial homogeneity of annealed areas, their state of annealing, and the damage in the surface layers. 相似文献