Perhaps you should try some spelling variations:
thanh doi » thanh loi, thanh moi, thanh do
thanh di » thanh de, thanh do, thanh dinh
hieu van » hieu va, thien van, lieu va
te sach » toc sach
duc van » duc va, duc tan, duc manh
hoc duc » hoc duoc, hoc nuoc, hoc thuc
sach ky » sac ky, sach y, sach ty
van hoc » van hoa
ma hoi » mai hoi, ma hoa, me hoi
cua tu » cua tuc, cua su, cua cu

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: te sach ky nang ((ma hoi) OR (xa hoi)). hieu van hoc duc van ((thanh di) OR (thanh doi)) cua tu~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang ((ma hoi) or (xa hoi)). hieu van hoc duc van ((thanh di) OR (thanh doi)) cua tu~".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ((ma hoi) or (xa hoi)). hieu van hoc duc van ((thanh di) OR (thanh doi)) cua tu*.