Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cua triet, dua tren
hanh de » hanh ve, hanh kem
duc van » duc va, duc tan, duc manh
hau duc » huu duc, ha duc, pham duc
van hau » van ha, van hai, van dau
mai hoi » mai khoi, dai hoi, lai hoi
cuu tre » cau tren, cau treo
sach v » sach va, sach y, sach 2
ma hoi » xa hoi, ma hoa, me hoi
v nang » va nang, vu nang, van nang

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: toc sach v nang ((ma hoi) OR (mai hoi)). hieu van hau duc van hanh de ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach v nang ((ma hoi) or (mai hoi)). hieu van hau duc van hanh de ((cua tre) OR (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: toc sach v nang ((ma hoi) or (mai hoi)). hieu van hau duc van hanh de ((cua tre) OR (cuu tre))*.