Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu van
hieu va » lieu va, hieu qua
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
tuc va » truc va, tuc xa, duc va
vai va » mai va, dai va, hai va
thiet » thieu

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