Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hanh vai » hanh vi, hanh va, hanh tai
hau thuc » huu thuc, ha thuc, mau thuc
hieu van » hieu va, thien van, lieu va
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
van hau » van ha, van hai, van dau
mai hoi » mai khoi, dai hoi, lai hoi
ky tang » ky nang, ky dang, kho tang
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet
ma hoi » xa hoi, ma hoa, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuoc sach) or (so sach)) ky tang ((ma hoi) OR (mai hoi)). hieu van hau thuc va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (so sach)) ky tang ((ma hoi) OR (mai hoi)). hieu van hau thuc va hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (so sach)) ky tang ((ma hoi) OR (mai hoi)). hieu van hau thuc va hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (so sach)) ky tang ((ma hoi) OR (mai hoi)). hieu van hau thuc va hanh vai cua tre*.