2Shlebak AA, Gordon MY, Marley SB, et al. Optional timing for pro- cessing and cryopreservation of umbilical cord haematopoietic stem clls forelinical transplantation . Bone Marrow ransplantation, 1999, 23(2) :131.
3Valeri CR, Pivacek LE. Effects of the temperature,the duration of f rozen storage, and the freezing container on in vitro measure-ments in human peripheral Blood mononuclear cells. Transfusion, 1996,36 (4) :303.
7Colaizzi P.Psychological research as the phenomenologists view it[M]//Vaile R,King M editors.Existential-phenomenological alternatives for psychology.New York:Oxford University Press,1978:48-71.
8Beck CT.Qualitative research:The evaluation of its credibility,fittingness.andauditability[J].Western Journal of Nursing Research,1993,15(1):263-266.
9Field MJ,Cassel CK.Approaching death:Improving care at the end of life[M].Washington(DC):National Academy Press,1997:http://www.search.nap.edu/readingroom/books/approaching/10.html.
10Ferrell B,Virani R,Grant M.Analysis of end of life content in nursing textbooks[J].Oncol Nurs Forum,1999,26(5):869-876.
5Karanes C,Nelson GO,Chitphakdithai P,et al.Twenty years of unrelated donor hematopoietic cell transplantation for adult recipients facilitated by the National Marrow Donor Program[J],Biol Blood Marrow Transplant,2008,14(9 Suppl):S8-15.