1. Measuring device for measuring magnetic resonance between magnetic moments in an object and a multi-dimensional magnetic field including static and oscillating components, comprising: probe means for detecting static and oscillating components of a magnetic field and for outputting first and second signals respectively representative thereof; resultant generating means receiving said first signals for generating and outputting a resultant signal representative of a resultant magnitude of the static component of said magnetic field; filter means responsive to said resultant signal for establishing a central frequency for filtering said second signals representative of said oscillating component of said magnetic field and for outputting filtered signals representative of the oscillating component of the magnetic field; phase analyzing means receiving said filtered signals for outputting phase signals and magnitude signals respectively indicative of phases and magnitudes of the oscillating component of the magnetic field; and yield determining means receiving said phase signals, said magnitude signals, and said first signals for determining a resonance yield of said magnetic field, thereby identifying a change in a rate of chemical reactions involving resonances between the magnetic moments in the object and the multi-dimensional magnetic field.