Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hieu van » hieu va, thien van, lieu va
benh dai » benh tai, benh noi, binh dan
sach ky » sac ky, sach y, sach ty
van cam » van nam, van lam, van cau
duc van » duc va, duc manh, duc phan
cua tre » cua te, cuu tre, cua triet
ma hoi » mai 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: thuat sach ky nang ((ma hoi) OR (xa hoi)). hieu van cam ((duc tan) or (duc van)) benh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ky nang ((ma hoi) OR (xa hoi)). hieu van cam ((duc tan) OR (duc van)) benh dai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ky nang ((ma hoi) OR (xa hoi)). hieu van cam ((duc tan) or (duc van)) benh dai cua tre*".