Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
thanh vi » hanh vi, thanh va, thanh ve
sach ky » sac ky, sach y, sach ty
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
qua cai » qua hai, qua cac, qua ca
cua tre » cua te, cuu tre, cua triet
xuc va » tuc va, luc va, xac va
vi cua » vai cua, di cua

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 ((nang ma) OR (tang ma)) hoi. hieu qua cai ((xuc va) or (duc va)) thanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang ma) OR (tang ma)) hoi. hieu qua cai ((xuc va) OR (duc va)) thanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((nang ma) OR (tang ma)) hoi. hieu qua cai ((xuc va) or (duc va)) thanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang ma) OR (tang ma)) hoi. hieu qua cai ((xuc va) or (duc va)) thanh vi cua tre*.