A complex nursing intervention of complementary and alternative medicine (CAM) to increase quality of life in patients with breast and gynecologic cancer undergoing chemotherapy: study protocol for a partially randomized patient preference trial$nElektronische Ressource - Klafke, Nadja; Mahler, Cornelia; Hagens, Cornelia von; Rochon, Justine; Schneeweiss, Andreas; Joos, Stefanie; Salize, Hans Joachim (Trials, 2015)