Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
xac va » tac va, ac va, bac va
luc va » duc va, tuc va, loc va
vi cua » vai cua, di cua
ve cac » va cac, vien cac

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) or (thuoc sach)) ky nang ma hoi. hieu ve cac ((xac va) or (luc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuoc sach)) ky nang ma hoi. hieu ve cac ((xac va) OR (luc va)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuoc sach)) ky nang ma hoi. hieu ve cac ((xac va) or (luc va)) hanh vi cua tre*.