全文获取类型
收费全文 | 74篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
化学 | 49篇 |
数学 | 13篇 |
物理学 | 14篇 |
出版年
2024年 | 2篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2016年 | 2篇 |
2014年 | 2篇 |
2013年 | 1篇 |
2012年 | 3篇 |
2011年 | 9篇 |
2010年 | 2篇 |
2009年 | 26篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2004年 | 1篇 |
2002年 | 2篇 |
2001年 | 1篇 |
1999年 | 2篇 |
1995年 | 1篇 |
1991年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有76条查询结果,搜索用时 15 毫秒
11.
Hull-kernel topology on the set ∑(R) of prime ideals of a ring R with unity and without nilpotent elements is discussed. The restriction of this topology to the set π(R) of minimal prime ideals of R has been investigated in detail. The compactness of π(R) has been characterized in several ways. An interesting characterization of Baer rings is given.A functorial correspondence between the category of rings having the property that every prime ideal contains a unique minimal prime ideal and their minimal spectra is established. 相似文献
12.
13.
D. Banerjee S.V. Thakare R. Menon K. Krishnan 《Journal of Physics and Chemistry of Solids》2010,71(7):983-987
Phase transition from anatase to rutile for the 70 nm TiO2 crystallite has been investigated by the time differential perturbed angular correlation (TDPAC) technique. The study involved the annealing of the TiO2 nanocrystals, adsorbed with the nuclear probe (181Hf/181Ta) at trace level, at different temperatures for different durations. The TDPAC measurement was also supported by XRD measurement where the width of the peaks increases with the increase in annealing temperature indicating a crystal growth. The samples annealed up to 823 K for 4 h showed no phase transition, except for the growth of the crystallites. However, it showed phase transition at the same temperature (823 K), when annealed for longer duration, indicating the slower kinetics of the phase transition process. Further the sample, when annealed at 1123 K for 4 h, showed phase transition. It has also been observed that the 181Hf tracer, adsorbed on 70 nm anatase TiO2, diffuses from surface to bulk during the phase transition process and the extent of diffusion in anatase differs from that in rutile phase. However, surface to bulk mass-transfer is found to play a significant role in the phase transition process. 相似文献
14.
Ashok V. Borhade Dipak R. Tope Sachin S. Kushare Savita V. Thakare 《Research on Chemical Intermediates》2018,44(12):7459-7478
A novel fly ash supported NiO (FA–NiO) nanocomposite solid heterogeneous catalyst has been prepared by impregnation of Ni(NO3)2 · 6H2O on thermally activated fly ash (FA) support. FT-IR spectroscopy, X-ray diffraction analysis, scanning electron microscopy, TEM and BET techniques were employed to characterize the catalyst. The catalytic adeptness of FA–NiO was tested and optimized in xanthene formation. Catalyst gave very high yield and good purity. Stability of the catalyst could be promising as it easily recovered and reused giving a similar yield up to four cycles. FA–NiO is an efficient catalyst providing an environmentally clean process for xanthene formation and for developing a revolutionary way to use the majority of waste fly ash. Further, we have also performed docking simulation between 1ONF and a xanthene molecule to evaluate binding orientation and affinity of the ligand. 相似文献
15.
Highly effective direct synthesis of DMC from CH_3OH and CO_2 using novel Cu-Ni/C bimetallic composite catalysts 总被引:1,自引:0,他引:1
Novel Cu-Ni/C has been prepared and utilized as an efficient catalyst system in direct synthesis of DMC from CH3OH and CO2. 相似文献
16.
Poly(trimethylene terephthalate)(PTT) is an excellent fiber material.Its thermal degradation and isothermal crystalline behaviors were in this study investigated using thermogravimetric analysis(TGA),thermogravimetric analysis-Fourier transform infrared spectroscopy(TGA-FTIR) analysis,differential scanning calorimetry(DSC) and X-ray diffraction(XRD).The thermal degradation mechanism of PTT follows Mclafferty rearrangement principle.The PTTwithintrinsicviscosity(Ⅳ) of 0.74 dL/g has a maximum crystallinity... 相似文献
17.
Zhong Lv Zhang Zhi Jie Sun Fei Xue Xian Jin Luo Nai Yun Xiu Li Teng Zong Gen Peng 《中国化学快报》2009,20(8):921-923
A series of novel benzimidazole derivatives was synthesized and their anti-Coxsackie virus B_3(CVB_3) activity was evaluated in VERO cells.Compounds 9 and 10 exhibited better inhibitory activity than those of ribavirin(RBV) with IC_(50) values of 5.30 and 1.06μg/mL,respectively. 相似文献
18.
H. Naik S. V. Surayanarayana V. K. Mulik P. M. Prajapati B. S. Shivashankar K. C. Jagadeesan S. V. Thakare D. Raj S. C. Sharma P. V. Bhagwat S. D. Dhole S. Ganesan V. N. Bhoraskar A. Goswami 《Journal of Radioanalytical and Nuclear Chemistry》2012,293(2):469-478
The 238U(n, ??)239U reaction cross-section at average neutron energy of 3.7?±?0.3?MeV from the 7Li(p, n)7Be reaction has been determined using activation and off-line ??-ray spectrometric technique. The 238U(n, ??)239U and 238U(n, 2n)237U reaction cross-sections at average neutron energy of 9.85?±?0.38?MeV from the same 7Li(p, n)7Be reaction have been also determined using the above technique. The experimentally determined 238U(n, ??)239U and 238U(n, 2n)237U reaction cross-sections were compared with the evaluated data of ENDF/B-VII, JENDL-4.0, JEFF-3.1 and CENDL-3.1. The experimental values were found to be in general agreement with the evaluated value based on ENDF/B-VII, and JENDL-4.0 but not with the JEFF-3.1 and CENDL-3.1. The present data along with literature data in a wide range of neutron energies were interpreted in terms of competition between different reaction channels including fission. The 238U(n, ??)239U and 238U(n, 2n)237U reaction cross-sections were also calculated theoretically using the TALYS 1.2 computer code and were also found to be in agreement experimental data. 相似文献
19.
PEG-400 as an efficient reaction medium for the synthesis of 2,4,5-triaryl-1H-imidazoles and 1,2,4,5-tetraaryl-1H-imidazoles 总被引:1,自引:0,他引:1
An efficient protocol for the one-pot multicomponent synthesis of various 2,4,5-triaryl- IH-imidazoles and 1,2,4,5-tetraaryl-1H-imidazoles using PEG-400 as reaction medium is described. This method has the advantages of good yields, less pollution and simple reaction conditions. 相似文献
20.
Milind S. Thakare Nilesh S. Pawar Vishnu A. Adole Dipak B. Patil Vikas Patil 《印度化学会志》2022,99(10):100670
A novel strategy, involving anchoring and un-anchoring of coumarin based fluorophore, has been established for the selective detection of Au3+ species. Selective sensing of Gold (Au3+) was triggered due to alkynophilicity of gold ions to create lateral fluorescence of a latent fluorophore. The 4-methyl-2-oxo-2H-chromen-7-yl 2-(2-phenylethynyl) benzoate (CEB) probe was synthesized by reacting 7-hydroxy-4-methylcoumarin with iodo-benzoic acid. CEB probe has an absorption at 300 nm and 335 nm which decreases gradually and new absorption appeared at 406 nm due to Au3+ promoted ester hydrolysis selectively over other metal ions with great sensitivity, which accompanies a turn on fluorescence change produced by 7-hydroxy coumarin. The principle behind this sensing strategy is activation of triple bond induced uniquely by Au+3 ions leading to cascade and delivers active fluorophore. The sensing mechanism was proposed and supported by 1H NMR, MS and TD-DFT experiments. The density functional theory (DFT) and time dependent density functional theory (TD-DFT) theoretical results of the CEB-probe and Au3+ reaction is in good agreement with the experimental results. Additionally, probe could be well incorporated onto the test strips for effective detection of Au3+. 相似文献