全文获取类型
收费全文 | 122篇 |
免费 | 0篇 |
专业分类
化学 | 58篇 |
力学 | 2篇 |
数学 | 5篇 |
物理学 | 57篇 |
出版年
2021年 | 1篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1997年 | 2篇 |
1996年 | 6篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有122条查询结果,搜索用时 902 毫秒
51.
52.
Ramón Macías Mark Thornton-Pett Trevor R. Spalding Bohumil Štíbr 《Journal of organometallic chemistry》2008,693(3):435-445
The reaction of [nido-7-SB10H12] with [RhCl(PPh3)3] in the presence of N,N,N′N′-tetramethylnaphthalene-1,8-diamine (tmnd) in CH2Cl2 gives twelve-vertex [2,2-(PPh3)2-2-H-closo-2,1-RhSB10H10] (1) and eleven-vertex [8,8-(PPh3)2-nido-8,7-RhSB9H10] (2), as major products, plus the dimeric species [{(PPh3)-closo-RhSB10H10}2] (3) as a minor product. Reaction of 1 with PMe2Ph in CH2Cl2 results in phosphine exchange and hydride substitution, affording the chloro analogue of 1, [2,2-(PMe2Ph)2-2-Cl-closo-2,1-RhSB10H10] (4). By contrast, reaction between [IrCl(PPh3)3] and [nido-7-SB10H12] in CH2Cl2 with tmnd affords only one product, twelve-vertex [2,2-(PPh3)2-2-H-closo-2,1-IrSB10H10] (5). [RhCl2(η5-C5Me5)]2 with [nido-7-SB10H12] under the same conditions gives twelve-vertex [2-(η5-C5Me5)-closo-2,1-RhSB10H10] (6). All the compounds are characterised by NMR spectroscopy, and by mass spectrometry, and the molecular structure of [2,2-(PMe2Ph)2-2-Cl-closo-2,1-RhSB10H10] (4) was established by single-crystal X-ray diffraction analysis. This last rhodathiaborane 4 is fluxional in solution through a process that involves a reversible partial rotation of the {RhCl(PMe2Ph)2} unit above the {SB4} pentagonal face of the {SB10H10} fragment. 相似文献
53.
54.
Forward particle production in π−
p andK
−
p collisions at 58 GeV/c and comparison with quark models
F. Pauß A. Gonzalez-Arroyo W. Ochs B. Alper G. Blanar M. Cerrada V. Chabaud C. Damerell C. Daum H. Dietl A. Gillman C. Hardwick W. Hoogland R. Klanner J. Loken E. Lorenz G. Lütjens G. Lutz W. Männer G. Polok M. Rozanska W. Spalding U. Stierlin G. Thompson H. Tiecke J. Turnau P. Weilhammer F. Wickens ACCMOR Collaboration 《Zeitschrift fur Physik C Particles and Fields》1985,27(2):211-232
We present single inclusive π±, π0 andK ± spectra in the forward fragmentation region (x>0.2,p T <1.5 GeV/c) as well as correlations between two charged particles. The data were recorded in an unseparated negative hadron beam at the CERN SPS using a large acceptance forward spectrometer. Our maasurements are compared in detail with several models which emphasise the role of the beam valence quarks in this production process. The connection to measurements at largep T is also investigated. 相似文献
55.
56.
Bould J Greatrex R Kennedy JD Ormsby DL Londesborough MG Callaghan KL Thornton-Pett M Spalding TR Teat SJ Clegg W Fang H Rath NP Barton L 《Journal of the American Chemical Society》2002,124(25):7429-7439
Single-crystal conventional-tube and synchrotron X-ray diffraction studies of the anions in [NMe(4)][arachno-B(9)H(12)-4,8-Br(2)] 1 and K[arachno-B(9)H(14)] 2, and also of the series of adducts [arachno-B(9)H(13)-4-L], where L is P(CCH)(3) (3), NHEt(2) (4), NC(5)H(5) (5), or NH(2)CH(2)Ph (6), are reported. Structural studies of 1-6, determined at low temperatures, located all atoms, including bridging and endo-terminal hydrogen atoms. The basic boron-hydride clusters of these, and of all the other known species with the arachno nine-vertex i-nonanborane geometry reported in the literature, are isostructural and feature three bridging and two endo-terminal hydrogen atoms on the open face. This arrangement is different from that previously reported for Cs[arachno-B(9)H(14)] 7 and for [arachno-B(9)H(13)-4-(NCMe)] 9. However, a new X-ray diffraction data set and refinement experimentally confirm the [3 x mu-H, 2 x endo] arrangement for 9 also. The experimental results for 1-6 support recently reported calculations for [B(9)H(14)](-), which predict both the structures and the (11)B NMR chemical shifts. These conclusions are also supported by calculations for 3, 4, and 9 and also for the [arachno-B(9)H(13)-4-(NCS)](-) anion in [NMe(4)][B(9)H(13)(NCS)] 8. 相似文献
57.
Hanrahan JP Copley MP Ziegler KJ Spalding TR Morris MA Steytler DC Heenan RK Schweins R Holmes JD 《Langmuir : the ACS journal of surfaces and colloids》2005,21(9):4163-4167
In this paper we investigate the use of supercritical carbon dioxide (sc-CO(2)) for synthesizing calcined mesoporous silicas with tunable pore sizes, wall thickness, and d spacings. Small angle neutron scattering was used to probe the controlled swelling of the triblock copolymer surfactant templating agents, P123 (PEO(20)PPO(69)PEO(20)), P85 (PEO(26)PPO(39)PEO(26)), and F127 (PEO(106)PPO(70)PEO(106)), as a function of CO(2) pressure. The transition from the liquid crystal phase to the calcined mesoporous silicas, formed upon condensation and drying, was also studied in detail. Powder X-ray diffraction, transmission electron microscopy, and nitrogen adsorption techniques were used to establish pore diameters, silica wall widths, and the hexagonal packing of the pores within the calcined silicas. Using a direct templating method, the diameters of mesopores and the spacing between the pores could be tuned with a high level of precision. The swelling process was observed to have no detrimental effects on the quality of silica formed, a distinct advantage over conventional swelling techniques, and all of the silicas synthesized in this study were highly ordered over distances of at least 2000 A. 相似文献
58.
59.
George Ferguson John F. Gallagher Trevor R. Spalding F. Tony Deeney 《Journal of organometallic chemistry》2005,690(12):2888-2894
Five new gold acetylides, [AuCCR], with hydroxyl or amino functions in the organic radical R have been prepared. From these, nine phosphine complexes [(R3P)AuCCR] with R = Ph or Cy were synthesised. Reactions between the phosphine gold acetylides [(Ph3P)AuCCC(Me)(OH)Et] or [(Cy3P)AuCCC(Me)(OH)Et] and the iron carbonyl cluster [Et4N][Fe4N(CO)12] gave both neutral [(R3P)AuFe4N(CO)12] and ionic compounds [(R3P)2Au][Fe4N(CO)12]. Reaction with the penta-iron cluster [Et4N][Fe5N(CO)14] afforded [(R3P)2Au][Fe5N(CO)14], [(R3P)2Au][Fe4N(CO)12] and [(R3P)AuFe4N(CO)12]. The gold-iron clusters were characterised with spectroscopic methods (IR, NMR and Mössbauer) and in the case of [(Cy3P)AuFe4N(CO)12] a single-crystal X-ray analysis. 相似文献
60.
W. D. James F. F. Arnold K. R. Pond M. D. Glascock T. G. Spalding 《Journal of Radioanalytical and Nuclear Chemistry》1984,83(2):209-214
The use of prompt gamma activation analysis (PGAA) as a method for detection of the intestinal rare earth marker, samarium, has been evaluated by comparison with thermal neutron activation analysis (NAA). PGAA detection has significant advantages with respect to its higher reaction cross section and possible rapid experimental turnaround time. Serious disadvantages are lower neutron fluxes available to the target and nonavailability of numerous PGAA facilities. Results of the technique comparisons are generally very good. Pony fecal concentrations of samarium in samples obtained at various times after administration of a marked meal were measured by both techniques. In only one sample did results of the methods differ by more than the experimental errors involved. 相似文献