1. A method for magnetic resonance imaging by partial parallel acquisition of magnetic resonance data from an examination subject, comprising the steps of: exciting nuclear spins in an examination subject by radiating the subject with radio frequency energy in a plurality of steps, and thereby exciting a magnetic resonance signal in the subject, and simultaneously receiving the magnetic resonance signal with each of a plurality of N component coils; for each of said N component coils, forming an incomplete data set of the received magnetic resonance signals, and acquiring additional calibration data points for each incomplete data set, thereby forming N incomplete datasets; reducing said N incomplete data sets to a subset of M reduced incomplete data sets, with M<N, by applying an N×M reduction matrix of eigenvectors to said N incomplete data sets, thereby obtaining M reduced, incomplete data sets; forming M complete data sets by applying an N×M reconstruction matrix to said M, incomplete data sets, causing non-measured lines of said M, incomplete data sets to be reconstructed with reconsideration of all of said N incomplete data sets; and spatially transforming said M complete data sets to form a complete image data set from each of said M complete data sets.