Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
cau treo » cau theo, cau tren, cau triet
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
hieu ve » hieu va, hieu van
cac xuc » cam xuc, cac nuoc, chat xuc
va dinh » van dinh, va kinh, va tinh
dinh vi » dinh ve, dinh viet, dinh tri
cuu tre » cua tre, cau tren
xuc va » duc va, tuc va, luc va
ve cac » va cac, vien cac

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach y ((nang ma) OR (tang ma)) hoi. hieu ve cac xuc va dinh vi ((cuu tre) OR (cau treo))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach y ((nang ma) or (tang ma)) hoi. hieu ve cac xuc va dinh vi ((cuu tre) OR (cau treo))~".
• Adding a wildcard symbol may retrieve word variants: doc sach y ((nang ma) or (tang ma)) hoi. hieu ve cac xuc va dinh vi ((cuu tre) OR (cau treo))*.