Catalyzes the hydrolysis of the N-glycosidic bond of purine and/or pyrimidine nucleosides into ribose and the base. a purine D-ribonucleoside + H2O = a purine nucleobase + D-ribose a pyrimidine ribonucleoside + H2O = a pyrimidine nucleobase + D-ribose Purine metabolism; purine nucleoside salvage. Belongs to the IUNH family.