Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hanh lam » thanh lap, hanh kem, hanh va
hanh lai » hanh tai, thanh lap, thanh loi
chat duc » chat xuc, chat doc, chet duoc
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
hieu ve » hieu van
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky sang ma hoi. ((hieu ve) or (hieu va)) chat duc va ((hanh lai) OR (hanh lam)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky sang ma hoi. ((hieu ve) OR (hieu va)) chat duc va ((hanh lai) OR (hanh lam)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky sang ma hoi. ((hieu ve) or (hieu va)) chat duc va ((hanh lai) OR (hanh lam)) cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky sang ma hoi. ((hieu ve) or (hieu va)) chat duc va ((hanh lai) OR (hanh lam)) cua tre*.