Perhaps you should try some spelling variations:
tai khoi » tai khoa, mai khoi, tao khoi
va trien » va truyen, va thiet, va tuyen
hoc sac » hoc sach, hoc cac, hoc mac
tai hoi » dai hoi, tai hai, tai hoe
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
va hanh » van hanh, va thanh, va danh
sac ky » cac ky, sai ky
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sac ky nang ((tai hoi) OR (tai khoi)). hieu ve pham duc va hanh vi ((cua te) or (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sac ky nang ((tai hoi) OR (tai khoi)). hieu ve pham duc va hanh vi ((cua te) OR (va trien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sac ky nang ((tai hoi) OR (tai khoi)). hieu ve pham duc va hanh vi ((cua te) or (va trien))".
• Adding a wildcard symbol may retrieve word variants: hoc sac ky nang ((tai hoi) OR (tai khoi)). hieu ve pham duc va hanh vi ((cua te) or (va trien))*.