Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
hanh trinh » canh tranh, hanh chinh
trinh ghep » trinh he, trinh nghe, trinh phap
trinh nha » trinh phan, trinh chat, trinh chao
co hanh » co thanh, co phanh, co anh
ghep tu » nghiep tu, ghep tuoi
tu hoc » te hoc
du hoc » duoc hoc

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (( co hanh trinh ghep tu hoc ) OR ( duy khanh ((trinh nha) OR (trinh nghien)) du hoc ))~.
• Adding a wildcard symbol may retrieve word variants: (( co hanh trinh ghep tu hoc ) or ( duy khanh ((trinh nha) or (trinh nghien)) du hoc ))*.