3Popay J,Rogers A,Williams G.Rationale and standards for the systematic review of qualitative literature in health services research[J].Qual Health Res,1998,8(3):341-351.
4Blumer H.Critiques of research in the social sciences:an appraisal of Thomas and Znaniecki's "the Polish peasant in Europe and America"[M].New Brunswick,New Jersey:Transaction,Inc,1979:80-82.
5Colaizzi P.Psychological research as the phenomenologist views it[M]//Valle R S,King M.Existential phenomenological alternatives for psychology.New York:Oxford University Press,1978:487.
6Twinn S.The evaluation of the effectiveness of health education interventions in clinical practice[J].J Adv Nurs,2001,34(2):230-237.
7Coyne I T.Sampling in qualitative research.Purposeful and theoretical sampling; merging or clear boundaries?[J].J Adv Nurs,1997,26(3):623-630.
