Perhaps you should try some spelling variations:
dau triet » cau triet, dau tien, su triet
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
duc van » duc manh, duc phan, duc hanh
san dau » van dau, san diu, ban dau

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: thu sach ky lang xa hoi. hieu van nam ((((duc van) OR (duc tan))) OR (duc va)) thanh san dau triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky lang xa hoi. hieu van nam ((((duc van) OR (duc tan))) or (duc va)) thanh san dau triet~".
• Adding a wildcard symbol may retrieve word variants: thu sach ky lang xa hoi. hieu van nam ((((duc van) OR (duc tan))) or (duc va)) thanh san dau triet*.