Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
hang tai » hang va, dung tai
tuc van » thuc van, truc van, tuc va
cam tuc » cam xuc, cam tu, nam thuc
hieu va » lieu va, hieu qua
tu sach » thu sach, te sach, tu cach
hieu ve » hieu van
tai hoi » tai khoi, dai hoi, tai hai
ly hang » ly quang
su sach » so sach, vu sach
vai su » va su, van su, lai su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (su sach)) ly hang tai hoi. ((hieu ve) OR (hieu va)) cam tuc van hanh vai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ly hang tai hoi. ((hieu ve) OR (hieu va)) cam tuc van hanh vai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ly hang tai hoi. ((hieu ve) OR (hieu va)) cam tuc van hanh vai su triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ly hang tai hoi. ((hieu ve) OR (hieu va)) cam tuc van hanh vai su triet*.