全文获取类型
收费全文 | 121篇 |
免费 | 2篇 |
专业分类
化学 | 33篇 |
力学 | 1篇 |
数学 | 7篇 |
物理学 | 82篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2020年 | 4篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 6篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1982年 | 1篇 |
1980年 | 9篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1976年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1933年 | 2篇 |
1915年 | 1篇 |
1913年 | 1篇 |
1909年 | 2篇 |
排序方式: 共有123条查询结果,搜索用时 0 毫秒
51.
Conradson SD Manara D Wastin F Clark DL Lander GH Morales LA Rebizant J Rondinella VV 《Inorganic chemistry》2004,43(22):6922-6935
Analysis of X-ray absorption fine structure spectra of UO(2+x) for x = 0-0.20 (UO(2)--U(4)O(9)) reveals that the adventitious O atoms are incorporated as oxo groups with U--O distances of 1.74 A, most likely associated with U(VI), that occur in clusters so that the UO(2) fraction of the material largely remains intact. In addition to the formation of some additional longer U--O bonds, the U sublattice consists of an ordered portion that displays the original U--U distance and a spectroscopically silent, glassy part. This is very different from previous models derived from neutron diffraction that maintained long U--O distances and high U--O coordination numbers. UO(2+x) also differs from PuO(2+x) in its substantially shorter An-oxo distances and no sign of stable coordination with H(2)O and its hydrolysis products. 相似文献
53.
54.
55.
B.J. Hall R.J. Ellis G.R. Dyck C.A. Lander R. Beach K.S. Sharma R.C. Barber H.E. Duckworth 《Physics letters. [Part B]》1984,138(4):260-262
The Manitoba II high-resolution mass spectrometer has been used to determine eight precise atomic mass differences amongst 124Sn, 124Te, 124Xe, 13C37Cl3 and 54Fe35Cl2. Precise values have been derived for the double β- decay energies of 124Xe and 124Sn and for the masses of 124Sn, 124Te, 124Xe and 54Fe. The precision of the mass of 124Xe has been improved by a factor of ≈150. 相似文献
56.
E. Blasius und H. Lander 《Fresenius' Journal of Analytical Chemistry》1980,303(4):272-278
Zusammenfassung Pyrolyse-Gas-Chromatogramme und Pyrolyse-Massenspektren von durch Kondensation, Substitution und Copolymerisation hergestellten Austauschern mit unterschiedlichen cyclischen Polyethern als Ankergruppen lassen charakteristische Bruchstücke erkennen. Sie können als Strukturmerkmale zur Identifizierung unbekannter analoger Austauscher dienen.Ein Analysengang zeigt die Reihenfolge des Einsatzes der beiden Analysenverfahren auf. Die nur einige Minuten beanspruchende Pyrolyse-Massenspektrometrie gibt Hinweise auf die Herstellung der Polymeren und eventuell eingesetzte Hilfsvernetzer. N-haltige Bruchstücke im Etherring werden durch den PND-Detektor angezeigt, wobei man mono- und bicyclische Ankergruppe unterscheiden kann. Pyrolysebruchstücke aus den Etherringen geben Rückschlüsse auf ihre Größe sowie die Alkylbrücke zwischen den Etherheteroatomen. Quantitative Aussagen über Substitutions- und Vernetzungsgrad ermittelt man über Peakhöhenverhältnisse bzw. Bandenflächenverhältnisse.
Determination of structural details of exchangers with cyclic polyethers as anchor groups by pyrolysis gas-chromatography and pyrolysis mass-spectrometry
Summary Pyrolysis gas-chromatograms and pyrolysis mass-spectra of exchangers with different cyclic polyethers as anchor groups show characteristic fragments. They can be used as structural details for the identification of unknown exchangers with similar functional groups.Analytical instructions give the sequence of the two analytical methods. Pyrolysis mass-spectrometry, requiring only a few minutes, provides indications to the preparation of the polymers and the additional cross-linking reagent. For nitrogen-containing fragments, the PND-detector is used, which allows a distinction between mono- and bicyclic anchor groups. Conclusions may be drawn from the pyrolysis fragments of the ether rings in order to determine the size of the rings and of the alkyl bridges between the heteroatoms. The ratio of peak-heights and the ratio of peak-areas, respectively, give quantitative data about the degree of substitution and cross-linkage.
Für finanzielle Unterstützung danken wir der Deutschen Forschungsgemeinschaft, Bonn-Bad Godesberg. 相似文献
57.
Larissa Bessler Lea-Marie Vogt Marc Lander Dr. Christina Dal Magro Dr. Patrick Keller Dr. Jonas Kühlborn Dr. Christopher J. Kampf Prof. Dr. Till Opatz Prof. Dr. Mark Helm 《Angewandte Chemie (International ed. in English)》2023,62(11):e202217128
The fields of RNA modification and RNA damage both exhibit a plethora of non-canonical nucleoside structures. While RNA modifications have evolved to improve RNA function, the term RNA damage implies detrimental effects. Based on stable isotope labelling and mass spectrometry, we report the identification and characterisation of 2-methylthio-1,N6-ethenoadenosine (ms2ϵA), which is related to 1,N6-ethenoadenine, a lesion resulting from exposure of nucleic acids to alkylating chemicals in vivo. In contrast, a sophisticated isoprene labelling scheme revealed that ms2ϵA biogenesis involves cleavage of a prenyl moiety in the known transfer RNA (tRNA) modification 2-methylthio-N6-isopentenyladenosine (ms2i6A). The relative abundance of ms2ϵA in tRNAs from translating ribosomes suggests reduced function in comparison to its parent RNA modification, establishing the nature of the new structure in a newly perceived overlap of the two previously separate fields, namely an RNA modification damage. 相似文献
58.
1,l-Dimethyl-2,2,2-trichloroethyl has merit as a protecting group for P-O in the phosphite-triester synthesis of oligonucleotides. Use of this group enables one to simplify procedures for preparing active nucleoside phosphorochloridite reagents, to remove oligonucleotide phosphotriester intermediates intact from a solid support, and to conduct block syntheses in solution or on a silica support viaphosphite chemistry. Deprotection can be achieved by warming the trihaloethyl phosphotriesters with tributylphosphine. The high efficiency of the coupling and deprotection reactions for oligomers bound to an insoluble support make this chemistry especially attractive. 相似文献
59.
Aihara H Alston-Garnjost M Avery RE Barbaro-Galtieri A Barker AR Barnes AV Barnett BA Bauer DA Bengtsson H Bintinger DL Blumenfeld BJ Bobbink GJ Bross AD Buchanan CD Buijs A Cain MP Caldwell DO Chamberlain O Chien C Clark AR Cowan GD Crane DA Dahl OI Derby KA Eastman JJ Eberhard PH Eisner AM Enomoto R Erne FC Fujii T Gabioud B Gary JW Gorn W Hauptman JM Hofmann W Huth JE Hylen J Joshi UP Kamae T Kaye HS Kees KH Kenney RW Kerth LT Ko W Koda RI Kofler RR Kwong KK Lander RL Langeveld WG Layter JG 《Physical review letters》1986,57(1):51-54
60.
Lozinova T. A. Lobanov A. V. Lander A. V. 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2018,92(10):2065-2074
Russian Journal of Physical Chemistry A - Comparative results are presented from detecting hydrogen peroxide (H2O2) in aqueous solutions of adenine derivatives irradiated at 77 K in the near-UV... 相似文献