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21.
CM Silva MF Duarte ML Mira MH Florêncio K Versluis AJ Heck 《Rapid communications in mass spectrometry : RCM》1999,13(12):1098-1103
Fast atom bombardment, combined with high-energy collision-induced tandem mass spectrometry, has been used to investigate gas-phase metal-ion interactions with captopril, enalaprilat and lisinopril, all angiotensin-converting enzyme inhibitors.Suggestions for the location of metal-binding sites are presented. For captopril, metal binding occurs most likely at both the sulphur and the nitrogen atom. For enalaprilat and lisinopril, binding preferably occurs at the amine nitrogen. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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Comprehensive schools in the UK have the annual task of assigning their intake of new pupils to tutor groups. This case study describes how the problem has been addressed at one such school, where several factors are taken into account in order to make the groups as similar as possible and, since pupils have an induction day in June when they assemble in their tutor groups and meet their new tutors, where the time scale is short. Manual allocation has been used in the past, needing many staff-hours to achieve a satisfactory result. Heuristics implemented on a spreadsheet have enabled substantial savings in staff time and given more evenly balanced tutor groups. 相似文献
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Lasse Jrgensen Cehofski Anders Kruse Alexander Nrgaard Alsing Benn Falch Sejergaard Jonas Ellegaard Nielsen Anders Schlosser Grith Lykke Sorensen Jakob Grauslund Bent Honor Henrik Vorum 《Molecules (Basel, Switzerland)》2022,27(11)
Aflibercept is a frequently used inhibitor of vascular endothelial growth factor (VEGF) in the treatment of macular edema following central retinal vein occlusion (CRVO). Retinal proteome changes following aflibercept intervention in CRVO remain largely unstudied. Studying proteomic changes of aflibercept intervention may generate a better understanding of mechanisms of action and uncover aspects related to the safety profile. In 10 Danish Landrace pigs, CRVO was induced in both eyes with an argon laser. Right eyes were treated with intravitreal aflibercept while left control eyes received isotonic saline water. Retinal samples were collected 15 days after induced CRVO. Proteomic analysis by tandem mass tag-based mass spectrometry identified a total of 21 proteins that were changed in content following aflibercept intervention. In retinas treated with aflibercept, high levels of aflibercept components were reached, including the VEGF receptor-1 and VEGF receptor-2 domains. Fold changes in the additional proteins ranged between 0.70 and 1.19. Aflibercept intervention resulted in a downregulation of pigment epithelium-derived factor (PEDF) (fold change = 0.84) and endoplasmin (fold change = 0.91). The changes were slight and could thereby not be confirmed with less precise immunohistochemistry and Western blotting. Our data suggest that aflibercept had a narrow mechanism of action in the CRVO model. This may be an important observation in cases when macular edema secondary to CRVO is resistant to aflibercept intervention. 相似文献
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Reinhard Benn 《Chemical physics》1976,15(3):369-376
Pulsed Fourier transform NMR was used to study 1H-CIDNP arising from the thermolysis of di-t-butylmagnesium 1 and -zinc 2 and from the thermolysis and photolysis of di-t-butylmercury 3 in deuterated hydrocarbons as solvents. The decomposition of 1, 2, and 3 leads to metal, to the polarized disproportionation products isobutane 4 and isobutene 5 (rate constant kd), and to the unpolarized combination product 2,2,3,3-tetramethylbutane 6 (rate constant kc). Analysis of the ratio kd/kc as well as the activation entropies for the decomposition establish a radical mechanism for the main process. In the decomposition of 1 and 2 an A/E multiplet polarization of 4 and 5 is observed. This is opposite to the E/A polarization of these products arising during the thermolysis of 3. The photolysis of 3, however, leads to an A/E polarization of 4 and 5. The different phases of the multiplets indicate a decomposition of dialkylmercury in a cage reaction. Dialkylmagnesium and -zinc, however, decompose in a free-radical reaction of uncorrelated t-butyl pairs. 相似文献
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The structure, thermal stability and decomposition of solutions of diallylzinc (I), bis(2-methylallyl)zinc (II), bis(3-methylallyl)zinc (III) and bis(3,3-dimethylallyl)zinc (IV) in deuterated solvents, have been investigated by1H NMR and by kinetic measurements at temperatures between ?125 and +180°C. At room temperature I, II, III and IV are dynamic systems and are best described as being rapidly equilibrating mixtures of all isomeric σ-allyl forms; the NMR spectra are averages weighted according to the relative concentrations of the respective forms. I displays a1H NMR spectrum of a static σ-allyl system only below ?125°C and II only below ?115°C. At temperatures above 100°C the thermal decomposition of I–IV results in coupling of the allyl groups, decomposition via radicals being the major process. The coupled products exhibit CIDNP, in which the multiplet polarisations confirm a decomposition via randomly diffusing allyl radicals. In the allyl radicals CH2CR1CR2R3 an alternating spin density was proved experimentally. The thermal stability decreases in the order I > II > III > IV. 相似文献
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This paper describes a rapid technique for reconstruction of the internal area function of a duct using blockage-induced eigenvalue shifts determined from eigenfrequencies measured under two sets of duct termination boundary conditions. A single broad band maximum length sequence (MLS) measurement of short duration is utilized to obtain the transfer function of the duct, which in turn can be utilized to determine its eigenvalue shifts and subsequently its internal area function using an inverse perturbation technique. The reconstruction results display the same order of accuracy as those obtained previously using swept sine measurements of extended duration. An expression for the determination of the area function is presented utilizing resonant frequency information alone, thus rendering duct length determination unnecessary. A computational routine further simplifies the process such that the accuracy of the technique could be ascertained for a range of configurations including longer ducts and ducts that initially have nonuniform internal cross section over their length. Development of a relationship between obstacle length and wavelength of the lowest eigenfrequency required for successful reconstruction is also described. This is an important result for longer ducts where measurement of lower eigenfrequencies may present problems using standard measurement equipment. 相似文献