Perhaps you should try some spelling variations:
sua viet » su viet, cua viet, lua viet
hanh dai » hanh tai, hanh dao, vanh dai
dai sua » dai cua
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
tuc va » truc va, tuc xa, duc va

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 ky tang xa hoi. ((hieu va) or (hieu qua)) cam ((tuc va) OR (thuc va)) hanh dai sua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky tang xa hoi. ((hieu va) OR (hieu qua)) cam ((tuc va) OR (thuc va)) hanh dai sua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky tang xa hoi. ((hieu va) or (hieu qua)) cam ((tuc va) OR (thuc va)) hanh dai sua viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky tang xa hoi. ((hieu va) or (hieu qua)) cam ((tuc va) OR (thuc va)) hanh dai sua viet*.