MagnetismhadbeenutilizedsinceancestralChineseinventingthecompass.Now,itplaysaveryimportantparteitherinourlifeorinscienceandtechnology.Forexample,radioandtelevisioncannotworkwithoutmagneticfield;peoplecuresomediseases,changetheactivityofyeastswithmagneticf (共 7633 字) [阅读本文] >>