全文获取类型
收费全文 | 71篇 |
免费 | 0篇 |
专业分类
化学 | 16篇 |
数学 | 5篇 |
物理学 | 50篇 |
出版年
2021年 | 1篇 |
2020年 | 2篇 |
2018年 | 1篇 |
2016年 | 3篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 1篇 |
2010年 | 2篇 |
2009年 | 7篇 |
2008年 | 2篇 |
2007年 | 5篇 |
2005年 | 1篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1997年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
排序方式: 共有71条查询结果,搜索用时 31 毫秒
51.
A new method for the determination of ion exchange equilibrium constants is developed. A technique based in the application of potentiometric titrations is used in the study of non selective strong acidic resins. Potentiometric titrations are carried out without constant ionic strength, so a mathematical treatment is developed in order to take into account the estimation of the activity coefficients and the liquid junction potentials. The ion exchange thermodynamic equilibrium constants for two resins, Dowex CM-15 and Dowex C650, between the proton form and the alkaline metals at 25 degrees C are given. 相似文献
52.
U.C. Bergmann M.J.G. Borge J. Cederkäll C. Forssén E. Fumero H.O.U. Fynbo H. Gausemel H. Jeppesen B. Jonson K. Markenroth T. Nilsson G. Nyman K. Riisager H. Simon O. Tengblad L. Weissman F. Wenander K. Wilhelmsen Rolander 《The European Physical Journal A - Hadrons and Nuclei》2001,12(3):279-284
The β-decays of the neutron-rich nuclei 12Be and 29Ne have been studied. The statistical correlations between the almost identical half-lives of 12Be and its daughter 12B are analysed for a large sample of 12Be decay data. Stringent mutual bounds are obtained on the parameter set, leading to a precise determination of the 12Be half-life of 21.50±0.04 ms. From a simultaneous detection of β-particles and neutrons from the decay of 29Ne the neutron emission probability, Pn, is determined to 17±5%. No indication of two-neutron emission is seen from this nucleus. An upper limit of 2.2% (90% confidence
level) is established for P2n.
Received: 3 May 2001 / Accepted: 6 August 2001 相似文献
53.
Kota Yamamoto Dr. Enol López Dr. Pablo Barrio Dr. Javier Borge Prof. Luis A. López 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(31):6999-7003
Gold-catalysis has enabled new synthetic opportunities in the chemistry of vinyldiazo compounds. Herein, we report the gold-catalyzed reaction of stabilized vinyldiazo compounds with pinacol alkenylboronates to provide boryl-functionalized cyclopentene derivatives through a formal [3+2] carbocycloaddition reaction, a very unusual pathway in alkenylboronate chemistry. This reaction proceeds with high regio- and stereoselectivity. The synthetic usefulness of the resulting borylated cyclopentene derivatives toward the synthesis of densely functionalized cyclopentanoids is also demonstrated. 相似文献
54.
A. Algora L. Batist M. J. G. Borge D. Cano-Ott R. Collatz S. Courtin Ph Dessagne L. M. Fraile A. Gadea W. Gelletly M. Hellström Z. Janas A. Jungclaus R. Kirchner M. Karny G. Le Scornet Ch Miehé F. Maréchal F. Moroz E. Nácher E. Poirier E. Roeckl B. Rubio K. Rykaczewski J. L. Tain O. Tengblad V. Wittmann 《The European Physical Journal A - Hadrons and Nuclei》2003,20(1):199-202
55.
V. Z. Goldberg W. H. Trzaska G. V. Rogachev J. J. Kolata A. Andreyev C. Angulo M. J. G. Borge S. Cherubini G. Chubarian G. Crowley A. S. Fomichev M. Gorska M. Gulino M. S. Golovkov M. Huyse K. -M. Källman M. Lattuada T. Lönnroth M. Mutterer R. Raabe A. M. Rodin S. Romano M. V. Rozhkov B. B. Skorodumov C. Spitaleri O. Tengblad G. M. Ter-Akopian A. Tumino P. Van Duppen R. Wolski 《Acta Physica Hungarica A》2003,18(2-4):215-222
We consider various possibilities for studies of nuclear structure in resonance reactions induced by radioactive beam. We discuss investigations on both sides of nuclear stability as well as studies of the α-cluster structure of light nuclei applying the reverse geometry thick target method. 相似文献
56.
This paper considers the school situation in Odense, Denmark, in 1992. School children, according to a forecast for the various census districts of the city, are assigned to school facilities, existing and planned, by means of linear programming. The resulting solution gives an indication of where in the city there will be an excess or deficit of school capacity. This provides an easy way of evaluating alternative school system expansion plans. Sample results are given, and there is also a discussion of some implementation aspects of this case study. 相似文献
57.
M. J. G. Borge D. G. Burke F. Calaprice O. C. Jonsson G. Løvhøiden R. A. Naumann K. Nybø G. Nyman H. L. Ravn T. F. Thorsteinsen The ISOLDE Collaboration CERN Geneva Switzerland 《Zeitschrift für Physik A Hadrons and Nuclei》1986,325(4):429-434
Neutron-rich isotopes of radon, produced by spallation reactions in a ThC2 target and selected chemically, were mass-separated and used as samples for radiation counting experiments. Assignments of the activities to radon isotopes were confirmed by genetic relationships to the previously known francium daughters. The halflife for the new isotope227Rn is 23±1 s and that for226Rn is 7.4±0.1 min. X-rays,γ-rays, and conversion electrons from the223Rn activity were measured. The decay patterns ofK X-rays and known gamma transitions in the223Fr daughter yield a halflife of 23.2± 0.4 min for223Rn, in contrast to the value of 43± 5 min reported earlier. Energies, intensities, and likely multipolarities for the most prominent gamma transitions in the223Rn→223Fr decay are presented. 相似文献
58.
Flow-injection-hydride generation procedure for Se in electrolytic manganese was optimized by means of the experimental design approach. Instrumental variables like power supplied (P), sample (F) and argon (G) flow rates together with chemical variables like NaBH4 and HCl concentrations were studied. In case of the chemical variables, it was concluded that sodium tetrahydridoborate concentrations higher than 1.0% extinguished the plasma while HCl concentration should always be higher than 0.6 mol dm−3. The analysis of effects suggested that all the instrumental variables are significant factors, and the optimum conditions were P = 1550 W, F = 4.75 mL min−1 and G = 0.6 mL min−1. The influence of Mn was specially studied and it was concluded that the interferences were negligible if Mn is below 2.0 g L−1. In the same sense, the interferences of antimony(III), arsenic(V) and mercury(II) were also considered negligible. Finally, a detection limit of 0.0005% (w/w) was obtained (a repeatability R.S.D. <2.0% for all Se concentrations tried). Some manganese samples were also spiked with different concentrations of Se(IV) and the results demonstrated to be in good statistical agreement with expected values. 相似文献
59.
60.
K. Wallmeroth G. Bollen M. J. G. Borge J. Campos A. Dohn P. Egelhof J. Grüner H. -J. Kluge U. Krönert F. Lindenlauf R. B. Moore A. Rodriguez A. Venugopalan J. L. Wood ISOLDE Collaboration 《Hyperfine Interactions》1987,34(1-4):21-24
On-line resonance ionization mass spectrometry has been applied to determine the isotope shift and hyperfine structure of185–189Au and tne I=11/2 isomer of189Au in the 6s2S1/2 6p2P1/2=268 nm) transition. The Au atoms were obtained as daughters of mass-separated Hg isotopes produced at the ISOLDE facility at CERN, ionized by a three-step resonant photoionization process, detected and mass-selected by time of flight. A drastic change of the nuclear charge radius was observed between187Au and186Au, which is interpreted as an onset of strong deformation of 2 0.25 in186Au and185Au.This work has been supported by the Bundesministerium für Forschung und Technologie. One of us, J. Wood was supported in part by the U.S. Department of Energy, Contract DE-AS05-80 ER 10599. 相似文献