NMR or nuclear magnetic resonance spectroscopy is widely used as one of an armoury of instrumental techniques available for structure analysis in Chemistry. It relies on magnetic properties possessed by some nuclei, notably 1H, 13C, 19F and 31P. Proton NMR, also called PMR, is the commonest and in these pages is what is meant by NMR.
There are three pages: they deal principally with low-resolution NMR spectra since that is what A level demands; the third page also considers spin-spin splitting and high-resolution spectra.
There are more examples of NMR (and other) spectra in the spectra pages on this site.
Chemistry contents Basis of NMR The chemical shift Proton environment and NMR spectra