Perhaps you should try some spelling variations:
tinh viet » trinh viet, ninh viet, dinh viet
viet cua » viec cua, viet ca, viet qua
toc sach » hoc sach, doc sach, thuoc sach
va tinh » may tinh
cac dac » cac dan, cac dai, cac bac
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ty sang » ty xang, ty hang, duy sang
ma hoi » mai hoi, ma hoa, me hoi
ve cac » va cac, vien cac
dac va » duc va, day va, dat va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ty sang ((ma hoi) OR (xa hoi)). hieu ve cac dac va tinh viet cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ty sang ((ma hoi) OR (xa hoi)). hieu ve cac dac va tinh viet cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ty sang ((ma hoi) OR (xa hoi)). hieu ve cac dac va tinh viet cua tre*".