Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
thu xac » thau xay
hieu va » lieu va, hieu qua
dan mai » doan mai, ban mai, dan tai
xac ky » cac ky, sac ky, bac ky
cac bo » bac bo, cac co
va dan » ca dan, va dao, va dau
o hoi » co hoi, o hoc, o hoa
o hai » co hai, so hai, o lai
bo va » bao va, do va, so va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu xac ky nang ((o hoi) OR (o hai)). hieu va cac bo va dan mai va triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu xac ky nang ((o hoi) OR (o hai)). hieu va cac bo va dan mai va triet*".