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排序方式: 共有114条查询结果,搜索用时 15 毫秒
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2.
Wiosetek-Reske AM Wysocki S Bak GW 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(4-5):1172-1178
The absorption and fluorescence spectra of N-nonyl acridine orange are determined at room temperature (298 K) in cyclohexane, benzene, carbon tetrachloride, chloroform, chlorobenzene and dichloromethane. The ground state of dipole moment was obtained by impedance measurements using Guggenheim-Debeye's method. The experimental excited state dipole moment of N-nonyl acridine orange was determined using Bakhshiev's and Kawski-Chamma-Viallet's formulae and solvent polarity parameter proposed by Reichardt. These experimental results were completed with theoretical results using quantum chemical methods. The experimental (muexp=10.76 D) and theoretical (mucal=9.9 D) dipole moments in the ground and excited state (muexp*=14.56 D) were compared. 相似文献
3.
Subramaniam V Alves ID Salgado GF Lau PW Wysocki RJ Salamon Z Tollin G Hruby VJ Brown MF Saavedra SS 《Journal of the American Chemical Society》2005,127(15):5320-5321
Transmembrane proteins (TMPs), particularly ion channels and receptors, play key roles in transport and signal transduction. Many of these proteins are pharmacologically important and therefore targets for drug discovery. TMPs can be reconstituted in planar-supported lipid bilayers (PSLBs), which has led to development of TMP-based biosensors and biochips. However, PSLBs composed of natural lipids lack the high stability desired for many technological applications. One strategy is to use synthetic lipid monomers that can be polymerized to form robust bilayers. A key question is how lipid polymerization affects TMP structure and activity. In this study, we have examined the effects of UV polymerization of bis-Sorbylphosphatidylcholine (bis-SorbPC) on the photoactivation of reconstituted bovine rhodopsin (Rho), a model G-protein-coupled receptor. Plasmon-waveguide resonance spectroscopy (PWR) was used to compare the degree of Rho incorporation and activation in fluid and poly(lipid) PSLBs. The results show that reconstitution of Rho into a supported lipid bilayer composed only of bis-SorbPC, followed by photoinduced lipid cross-linking, does not measurably diminish protein function. 相似文献
4.
Huang Y Triscari JM Pasa-Tolic L Anderson GA Lipton MS Smith RD Wysocki VH 《Journal of the American Chemical Society》2004,126(10):3034-3035
Analysis of fragmentation patterns from 5654 unique doubly charged tryptic peptides is obtained. Great variability of average relative abundance of bond cleavage is found between different amino acid combinations. There exist similarities as well as differences between b and y ions. Strong enhancement or suppression of cleavage gives insight into possible chemical interactions at reactive conformations formed by preferred phi-psi angles. 相似文献
5.
Radosław Bonikowski Józef Kula Anna Bujacz Anna Wajs-Bonikowska Małgorzata Zakłos-Szyda Stanisław Wysocki 《Tetrahedron: Asymmetry》2012,23(14):1038-1045
Ten enantiomerically pure hydroindene-derived compounds obtained by the transformation of (+)-carotol, the main constituent of carrot seed essential oil, were examined for their ability to inhibit the growth of myeloid leukaemia (HL-60) cancer cell lines. All compounds showed significant activity, which was comparable to the most active volatile organic compounds, such as trans–trans-farnesol, citral and nerolidol. Based on the bioactivity and molecular modelling, a 3D QSAR pharmacophore model was generated. 相似文献
6.
Royston S. Quintyn Mowei Zhou Shai Dagan John Finke Vicki H. Wysocki 《International Journal for Ion Mobility Spectrometry》2013,16(2):133-143
Understanding protein tertiary and quaternary structures is crucial to a better understanding of their biological functions. Here we illustrate for tryptophan synthase that tandem mass spectrometry (MS/MS) reveals not only protein subunit architectures, but also protein unfolding behavior when coupled with ion mobility (IM). In the present study, we verified the subunit arrangement with surface induced dissociation (SID). We are able to correlate experimental results by IM with those obtained in unfolding simulations for the hetero-tetramer Tryptophan Synthase (TS) protein complex by identifying the presence of at least three stable intermediates (I1, I2, and I3) during the unfolding process in collision induced dissociation (CID). We illustrate that the unfolding of the TS complex is likely due to the initial unfolding of an α-monomer subunit, followed by the unfolding of the second α-monomers. We also illustrate the ability of this combination of techniques to not only identify conformational changes of TS upon addition of D,L-α-glycerol phosphate (GP), but also to determine the location of the ligand, which is buried within the α-monomer of the TS. 相似文献
7.
Xin Ma Lien B. Lai Stella M. Lai Akiko Tanimoto Mark P. Foster Vicki H. Wysocki Venkat Gopalan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(43):11667-11671
We demonstrate that surface‐induced dissociation (SID) coupled with ion mobility mass spectrometry (IM‐MS) is a powerful tool for determining the stoichiometry of a multi‐subunit ribonucleoprotein (RNP) complex assembled in a solution containing Mg2+. We investigated Pyrococcus furiosus (Pfu) RNase P, an archaeal RNP that catalyzes tRNA 5′ maturation. Previous step‐wise, Mg2+‐dependent reconstitutions of Pfu RNase P with its catalytic RNA subunit and two interacting protein cofactor pairs (RPP21⋅RPP29 and POP5⋅RPP30) revealed functional RNP intermediates en route to the RNase P enzyme, but provided no information on subunit stoichiometry. Our native MS studies with the proteins showed RPP21⋅RPP29 and (POP5⋅RPP30)2 complexes, but indicated a 1:1 composition for all subunits when either one or both protein complexes bind the cognate RNA. These results highlight the utility of SID and IM‐MS in resolving conformational heterogeneity and yielding insights on RNP assembly. 相似文献
8.
Biphenyl derivative N-allyl-N′-(4′-nitro[1,1′-biphenyl]-4-yl)thiourea (BP1) was synthesized as a functional fluorescent sensor for protons and their photophysical properties were studied. The influence of environment protonation on photophysical properties of the biphenyls in solutions was investigated using UV absorption, steady-state and time-resolved fluorescence spectroscopy. Semi-empirical and DFT calculations and optimization of the molecular structure of the biphenyl derivatives in vacuum, in polar solvents and in a proton-rich environment were conducted using the HyperChem, Amsol and Gaussian3 software package. Fluorescence quenching with addition of acidic acid was observed and the Stern-Volmer quenching rate constant was about 3.0×109 M−1 s−1. Intermolecular hydrogen bonds formations by the protons with the sulphur being substituted to the biphenyls generate charge movement and strong increase (×5) of the dipole moment of the fluorophore. 相似文献
9.
D. Weidmann G. Wysocki C. Oppenheimer F.K. Tittel 《Applied physics. B, Lasers and optics》2005,80(2):255-260
We report the development of a field-deployable, pulsed quantum cascade laser spectrometer. The instrument is designed to measure the 13C/12C isotopic ratio in the CO2 released from volcanic vents. Specific 12CO2 and 13CO2 absorption lines were selected around 4.3 m, where the P-branch of 12CO2 overlaps the R-branch of 13CO2 of the 0001–0000 vibrational transition. This particular selection makes the instrument insensitive to temperature variations. A dual-channel cell balances the two absorption signals. We provide details of the instrument design and a preliminary demonstration of its performance based on laboratory measurements of 16O12C16O and 16O12C18O. PACS 42.55.Px; 42.62.Fi; 07.88.+y 相似文献
10.
Ashley C. Gucinski Árpád Somogyi Julia Chamot-Rooke Vicki H. Wysocki 《Journal of the American Society for Mass Spectrometry》2010,21(8):1329-1338
A new approach that uses a hybrid Q-FTICR instrument and combines quadrupole collision-induced dissociation, hydrogen-deuterium
exchange, and infrared multiphoton dissociation (QCID-HDX-IRMPD) has been shown to effectively separate and differentiate
isomeric fragment ion structures present at the same m/z. This method was used to study protonated YAGFL-OH (free acid), YAGFL-NH2 (amide), cyclic YAGFL, and YAGFL-OCH3 (methyl ester). QCID-HDX of m/z 552.28 (C29H38N5O6) from YAGFL-OH reveals at least two distributions of ions corresponding to the b5 ion and a non-C-terminal water loss ion structure. Subsequent IRMPD fragmentation of each population shows distinct fragmentation
patterns, reflecting the different structures from which they arise. This contrasts with data for YAGFL-NH2 and YAGFL-OCH3, which do not show two distinct H/D exchange populations for the C29H38N5O6 structure formed by NH3 and HOCH3 loss, respectively. Relative extents of exchange for C29H38N5O6 ions from six sequence isomers (YAGFL, AGFLY, GFLYA, FLYAG, LYAGF, and LFGAY) show a sequence dependence of relative isomer
abundance. Supporting action IRMPD spectroscopy data are also presented herein and also show that multiple structures are
present for the C29H38N5O6 species from YAGFL-OH. 相似文献