Perhaps you should try some spelling variations:
te sach » toc sach
cac tac » cac toc, cac bac, cac dac
duoi ca » doi ca, cuoi cua, nuoi cay
xa dong » ha dong, van dong, lao dong
xa nong » xuat nong, may nong, cua nong
ca viet » va viet, co viet, hoa viet
hieu ve » hieu va, hieu van
van hoi » van hoa, van hoc, van hoe
ky tang » ky nang, ky dang, kho tang
ky lang » ky nang, ky dang, tay lang
ve cac » va cac, vien cac

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) OR (ky tang)) van hoi. hieu ve cac tac ((xa nong) or (xa dong)) duoi ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ky lang) OR (ky tang)) van hoi. hieu ve cac tac ((xa nong) OR (xa dong)) duoi ca viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ky lang) OR (ky tang)) van hoi. hieu ve cac tac ((xa nong) or (xa dong)) duoi ca viet*".