全文获取类型
收费全文 | 95篇 |
免费 | 2篇 |
专业分类
化学 | 62篇 |
力学 | 2篇 |
数学 | 15篇 |
物理学 | 18篇 |
出版年
2020年 | 2篇 |
2019年 | 2篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 9篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1940年 | 2篇 |
1937年 | 1篇 |
1932年 | 2篇 |
排序方式: 共有97条查询结果,搜索用时 807 毫秒
61.
D. A. Parkes 《国际化学动力学杂志》1977,9(3):451-469
Using the technique of molecular modulation spectrometry, we have measured directly the rate constants of several reactions involved in the oxidation of methyl radicals at room temperature: k1 is in the fall-off pressure regime at our experimental pressures (20–760 torr) where the order lies between second and third and we obtain an estimate for the second-orderlimit of (1.2 ± 0.6) × 10?12 cm3/molec · sec, together with third-order rate constants of (3.1 ± 0.8) × 10?31 cm6/molec2 · sec with N2 as third body and (1.5 ± 0.8) × 10?30 with neopentane; we cannot differentiate between k2a and k2c and we conclude k2a + (k2c) = (3.05 ± 0.8) × 10?13 cm3/molec · sec and k2b = (1.6 ± 0.4) × 10?13 cm3/molec · sec; k3 = (6.0 ± 1.0) × 10?11 cm3/molec · sec. 相似文献
62.
The governing equation of the dust fluid with non-thermal ions and
variable dust charge on dust particles in hot dust plasmas is
obtained. Both the compressive and rarefactive waves in this
system are investigated. They can be determined by plasma
parameters including the temperatures of dust fluid, ions and
electrons, as well as the non-thermal parameter of ions, and the
number densities of the dust particles, the ions and the
electrons, etc. 相似文献
63.
G. M. B. Parkes P. A. Barnes E. L. Charsley G. Bond 《Journal of Thermal Analysis and Calorimetry》1999,56(2):723-731
This paper describes a new instrument for performing thermal analysis using microwaves both as a form of heating and as a
novel means of detecting thermally induced transformations in materials. Results are presented for a selection of processes
including decompositions, dehydrations and phase changes. The capability of the instrument to be coupled with ancillary techniques
such as EGA is also demonstrated.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
64.
Self-Assembled Anion-Binding Cryptand for the Selective Liquid–Liquid Extraction of Phosphate Anions
Rebecca Andrews Sabera Begum Christopher J. Clemett Robert A. Faulkner Michael L. Ginger Jane Harmer Marco Molinari Gareth M. B. Parkes Zuhlqurnain M. H. Qureshi Craig R. Rice Michael D. Ward Howard M. Williams Philippe B. Wilson 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(46):20660-20664
The ligands L1 and L2 form trinuclear self-assembled complexes with Cu2+ (i.e. [( L1 )2Cu3]6+ or [( L2 )2Cu3]6+) both of which act as a host to a variety of anions. Inclusion of long aliphatic chains on these ligands allows the assemblies to extract anions from aqueous media into organic solvents. Phosphate can be removed from water efficiently and highly selectively, even in the presence of other anions. 相似文献
65.
N.B. Janson A. Pototsky C. Parkes 《The European physical journal. Special topics》2013,222(10):2623-2631
We studied the response of healthy volunteers to the delayed feedback generated from the breathing signals. Namely, in the freely-breathing volunteers the breathing signal was recorded, delayed by τ seconds and fed back to the same volunteer in real time in the form of a visual and auditory stimulus of low intensity, i.e. the stimulus was crucially non-intrusive. In each case volunteers were instructed to breathe in the way which was most comfortable for them, and no explanation about the kind of applied stimulus was provided to them. Each volunteer experienced 10 different delay times ranging between 10% and 100% of the average breathing period without external stimulus. It was observed that in a significant proportion of subjects (11 out of 24) breathing was slowed down in the presence of delayed feedback with moderate delay. Also, in 6 objects out of 24 the delayed feedback was able to induce transition from nearly periodic to irregular breathing. These observations are consistent with the phenomena observed in numerical simulation of the models of periodic and chaotic self-oscillations with delays, and also in experiments with simpler self-oscillating systems. 相似文献
66.
A procedure for finding the solutions of the Vakhnenko–Parkes equation by means of the inverse scattering method is described. Both the bound state spectrum and the continuous spectrum are considered in the associated eigenvalue problem. The suggested special form of the singularity function gives rise to periodic solutions. The interaction of a soliton with a one-mode periodic wave is studied. 相似文献
67.
Mikhailov VA Parkes MA Tuckett RP Mayhew CA 《The journal of physical chemistry. A》2006,110(17):5760-5771
A study of the reactions of a series of gas-phase cations (NH(4)(+), H(3)O(+), SF(3)(+), CF(3)(+), CF(+), SF(5)(+), SF(2)(+), SF(+), CF(2)(+), SF(4)(+), O(2)(+), Xe(+), N(2)O(+), CO(2)(+), Kr(+), CO(+), N(+), N(2)(+), Ar(+), F(+), and Ne(+)) with the three structural isomers of dichloroethene, i.e., 1,1-C(2)H(2)Cl(2), cis-1,2-C(2)H(2)Cl(2), and trans-1,2-C(2)H(2)Cl(2) is reported. The recombination energy (RE) of these ions spans the range of 4.7-21.6 eV. Reaction rate coefficients and product branching ratios have been measured at 298 K in a selected ion flow tube (SIFT). Collisional rate coefficients are calculated by modified average dipole orientation (MADO) theory and compared with experimental data. Thermochemistry and mass balance have been used to predict the most feasible neutral products. Threshold photoelectron-photoion coincidence spectra have also been obtained for the three isomers of C(2)H(2)Cl(2) with photon energies in the range of 10-23 eV. The fragment ion branching ratios have been compared with those of the flow tube study to determine the importance of long-range charge transfer. A strong influence of the isomeric structure of dichloroethene on the products of ion-molecule reactions has been observed for H(3)O(+), CF(3)(+), and CF(+). For 1,1-C(2)H(2)Cl(2) the reaction with H(3)O(+) proceeds at the collisional rate with the only ionic product being 1,1-C(2)H(2)Cl(2)H(+). However, the same reaction yields two more ionic products in the case of cis-1,2- and trans-1,2-C(2)H(2)Cl(2), but only proceeds with 14% and 18% efficiency, respectively. The CF(3)(+) reaction proceeds with 56-80% efficiency, the only ionic product for 1,1-C(2)H(2)Cl(2) being C(2)H(2)Cl(+) formed via Cl(-) abstraction, whereas the only ionic product for both 1,2-isomers is CHCl(2)(+) corresponding to a breaking of the C=C double bond. Less profound isomeric effects, but still resulting in different products for 1,1- and 1,2-C(2)H(2)Cl(2) isomers, have been found in the reactions of SF(+), CO(2)(+), CO(+), N(2)(+), and Ar(+). Although these five ions have REs above the ionization energy (IE) of any of the C(2)H(2)Cl(2) isomers, and hence the threshold for long-range charge transfer, the results suggest that the formation of a collision complex at short range between these ions and C(2)H(2)Cl(2) is responsible for the observed effects. 相似文献
68.
69.
Barry McCollum Paul McMullan Andrew J. Parkes Edmund K. Burke Rong Qu 《Annals of Operations Research》2012,194(1):291-315
Automated examination timetabling has been addressed by a wide variety of methodologies and techniques over the last ten years
or so. Many of the methods in this broad range of approaches have been evaluated on a collection of benchmark instances provided
at the University of Toronto in 1996. Whilst the existence of these datasets has provided an invaluable resource for research
into examination timetabling, the instances have significant limitations in terms of their relevance to real-world examination
timetabling in modern universities. This paper presents a detailed model which draws upon experiences of implementing examination
timetabling systems in universities in Europe, Australasia and America. 相似文献
70.