Perhaps you should try some spelling variations:
thanh cac » hanh cac, thanh bac, tranh cac
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
thanh ca » thanh cha, thanh ha, thanh va
te sach » toc sach
sach ky » sac ky, sach y, sach ty
van cac » van hac, van cau, van bac
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
duc ban » duc van, dua ban, duc man

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 ky lang xa hoi. hieu van cac ((duc ban) or (duc tan)) ((thanh ca) OR (thanh cac)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky lang xa hoi. hieu van cac ((duc ban) OR (duc tan)) ((thanh ca) OR (thanh cac)) cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky lang xa hoi. hieu van cac ((duc ban) or (duc tan)) ((thanh ca) OR (thanh cac)) cua viet".
• Adding a wildcard symbol may retrieve word variants: te sach ky lang xa hoi. hieu van cac ((duc ban) or (duc tan)) ((thanh ca) OR (thanh cac)) cua viet*.