Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
duc ban » duc tan, duc van, dua ban
xuc ban » cuc ban, quoc ban, xuat ban
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
sang ma » tang ma, nang ma, sang tao
anh vi » hanh vi, anh va, anh ve
vi cua » vai cua, di cua
va cao » va cac, va co, va dao

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 y ((sang ma) or (mang may)) hoi. hieu va cao ((xuc ban) or (duc ban)) anh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((sang ma) OR (mang may)) hoi. hieu va cao ((xuc ban) OR (duc ban)) anh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((sang ma) or (mang may)) hoi. hieu va cao ((xuc ban) or (duc ban)) anh vi cua tre*.