Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
van hanh » van thanh, ban hanh, van anh
tham xuc » tham nuoc, tham thuc, pham duc
nang mai » nang ma, nang tai, lang mai
hanh ki » hanh vi, hanh ky, hanh kien
xuc van » duc van, luc van, vuc van
tu sach » thu sach, te sach, tu cach
mai hoi » mai khoi, dai hoi, lai hoi
vu nang » vuc nang, va nang, vu dang
su sach » so sach, vu sach
hieu va » hieu qua
ki su » ky su

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: ((tu sach) OR (su sach)) vu nang mai hoi. ((hieu va) OR (lieu va)) tham xuc van hanh ki su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) vu nang mai hoi. ((hieu va) OR (lieu va)) tham xuc van hanh ki su triet~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) vu nang mai hoi. ((hieu va) OR (lieu va)) tham xuc van hanh ki su triet*.