全文获取类型
收费全文 | 72篇 |
免费 | 3篇 |
专业分类
化学 | 49篇 |
数学 | 17篇 |
物理学 | 9篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 7篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 5篇 |
2012年 | 5篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 4篇 |
2005年 | 1篇 |
2004年 | 5篇 |
2003年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 3篇 |
1977年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有75条查询结果,搜索用时 15 毫秒
51.
Alexander von Weber David C. Hooper Matthias Jakob Dr. Ventsislav K. Valev Dr. Aras Kartouzian Prof. Ueli Heiz 《Chemphyschem》2019,20(1):62-69
We have studied the circular dichroism (CD), in the ultraviolet and visible regions, of the transparent, chiral molecule 1,1’-Bi-2-naphtol (BINOL) in 1.5 μm thick films. The initial transparent film shows an additional negative cotton effect in the CD compared to solution. With time under room temperature the film undergoes a structural phase transition. This goes hand in hand with a cotton effect at the low energy absorption band which inverts with opposite propagation direction of light through the film which is revealed as a polarity reversal of ellipticity (PRE). After completion of the phase transition the film exhibits circular differential scattering throughout the visible range which also shows PRE. The structure change was studied with Raman, microscopy under cross polarization conditions and nonlinear second-harmonic generation circular dichroism (SHG-CD). The superposition of the optical activity of individual molecules and isotropy effects makes an interpretation challenging. Yet overcoming this challenge by finding a suitable model structural information can be derived from CD measurements. 相似文献
52.
Dielectric loss measurements are reported for polystyrene, crosslinked polystyrene, polyacrylamide, branched polyacrylamide, and poly(methyl methacrylate) at 1 and 10 kHz f over the temperature range ?85 to +100°C. Crosslinking and branching have a pronounced effect on the dielectric relaxation spectra of polymers. The methods of preparation of these polymers and their viscosity molecular weight data are also reported. 相似文献
53.
J. Vanderschueren L. Aras C. Boonen J. Niezette M. Corapci 《Journal of Polymer Science.Polymer Physics》1984,22(12):2261-2274
The relaxation behavior of n-butyl methacrylate/methacrylic acid (MAA) copolymers (12 mol % MAA) and their alkaline salts (K, Li) with various degrees of neutralization was investigated from 77 to 400 K by means of thermally stimulated depolarization and polarization methods. For degrees of neutralization higher than 50%, the experimental results were found to be consistent with the existence of complex heterophase structures involving significant widening of the distribution function of relaxation times in the glass transition region, splitting of the side-chain transition in several discrete relaxation components, and formation of ionic cluster giving rise to their own relaxation process. By systematically studying the influence of polarization conditions, it was also shown that the appearance and stability of such clusters are markedly dependent on the thermal and electrical history of the samples and that the clustering relaxation is closely related to the ionic conductivity via space-change formation. 相似文献
54.
A k-factor of a graph G is a k-regular spanning subgraph of G. A k-factorization is a partition of E(G) into k-factors. Let K(n, p) be the complete multipartite graph with p parts, each of size n. If \(V_{1},\ldots , V_{p}\) are the p parts of V(K(n, p)), then a holey k -factor of deficiency \(V_{i}\) of K(n, p) is a k-factor of \(K(n,p)-V_{i}\) for some i satisfying \(1\le i \le p\). Hence a holey k -factorization is a set of holey k-factors whose edges partition E(K(n, p)). Representing each (holey) k-factor as a color class in an edge-coloring, a (holey) k-factorization of K(n, p) is said to be fair if between each pair of parts the color classes have size within one of each other (so the edges are shared “evenly” among the permitted (holey) factors). In this paper the existence of fair 1-factorizations of K(n, p) is completely settled, as is the existence of fair holey 1-factorizations of K(n, p). The latter result can be used to provide a new construction for symmetric quasigroups of order np with holes of size n. Such quasigroups have the additional property that the permitted symbols are shared as evenly as possible among the cells in each \(n \times n\) “box”. These quasigroups are in some sense as far from frames produced by direct products as possible. 相似文献
55.
56.
Fluorine determination in human and animal bones by particle-induced gamma-ray emission 总被引:1,自引:0,他引:1
Sastri CS Iyengar V Blondiaux G Tessier Y Petri H Hoffmann P Aras NK Zaichick V Ortner HM 《Fresenius' Journal of Analytical Chemistry》2001,370(7):924-929
Fluorine was determined in the iliac crest bones of patients and in ribs collected from post-mortem investigations by particle-induced gamma-ray emission based on the 19F(p,p'gamma)19F reaction, using 2.0/2.5 MeV protons. The results indicate that for 68% of the human samples the F concentration is in the range 500-1999 microg g(-1). For comparison purposes fluorine was also determined in some animal bones; in some animal tissues lateral profiles of fluorine were measured. 相似文献
57.
58.
Imogen S. Parry Dr. Aras Kartouzian Dr. Suzanne M. Hamilton Dr. O. Petru Balaj Prof. Dr. Martin K. Beyer Prof. Stuart R. Mackenzie 《Angewandte Chemie (International ed. in English)》2015,54(4):1357-1360
We report the observation of chemical reactions in gas‐phase Rhn(N2O)m+ complexes driven by absorption of blackbody radiation. The experiments are performed under collision‐free conditions in a Fourier transform ion cyclotron resonance mass spectrometer. Mid‐infrared absorption by the molecularly adsorbed N2O moieties promotes a small fraction of the cluster distribution sufficiently to drive the N2O decomposition reaction, leading to the production of cluster oxides and the release of molecular nitrogen. N2O decomposition competes with molecular desorption and the branching ratios for the two processes show marked size effects, reflecting variations in the relative barriers. The rate of decay is shown to scale approximately linearly with the number of infrared chromophores. The experimental findings are interpreted in terms of calculated infrared absorption rates assuming a sudden‐death limit. 相似文献
59.
N. K. Aras G. Yilmaz S. Alkan F. Korkusuz 《Journal of Radioanalytical and Nuclear Chemistry》1999,239(1):79-86
There is an evidence that some of the essential trace elements are crucial determinants of bone health. Excess or deficiency
of these elements has a role in the development of bone diseases, therefore research on trace elements in bone is very important.
Iliac crest bone biopsies were optioned from twelve persons undergoing orthopedic surgery due to any reason than osteoporosis.
Cortical and trabecular parts were separated, and blood and fats were removed. Up to 30 minor and trace elements were determined
in these samples by instrumental neutron activation analysis and other techniques and their relations were discussed. 相似文献
60.
Abdülmelik Aras 《印度化学会志》2022,99(7):100553
In this study, 5-(2-hydroxy-4-methoxybenzylidenamino)-2-mercaptobenzimidazole and 5-(4-hydroxy-3-methoxybenzylidenamino)-2-mercaptobenzimidazole Schiff base compounds were synthesized and their structure were characterized with spectroscopic techniques, namely, 1H NMR, IR, and 13C NMR. In vitro ABTS, DPPH, CUPRAC, and FRAP tests were applied to calculate the antioxidant activities of the newly designed compounds. Beside, the enzyme inhibitory abilities of the mercaptobenzimidazole derivative Schiff base were assessed against the glutathione S-transferase (GST) enzyme. The Ki values were calculated as 20.06 ± 3.11 and 36.86 ± 6.17 μM, as well as the IC50 values were calculated as 6.30 μM and 5.33 μM respectively. Besides, molecular docking interactions of the compounds with the GST target enzyme (PDB ID:5JCU) were estimated via Chimera and AutoDock Vina software. ?8.7 kcal/mol, and ?8.5 kcal/mol were calculated as best binding scores of compounds against the GST enzyme. Since the novel Schiff base, 5-(4-hydroxy-3-methoxybenzylidenamino)-2-mercaptobenzimidazole has a good potential in the GST inhibition, it should be subjected to the further pharmacological studies. 相似文献