研究,study,research,discussion
领域,field,area,domain
排列组合,3×3=9,至少9种可能
如
study field
study domain
study area
research field
research domain
research area
discussion field
discussion domain
discussion area
其它,诸如area of research,field of study...就不一一枚举了
PS:investigation,调查研究,偏于“调查”,与“研究”不全等,慎用。
供参