Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
va trien » va truyen, va thiet, va tuyen
hoa hoi » khoa hoi, hoa doi, hoc hoi
sach ky » sac ky, sach ty, sach kem
hieu va » lieu va, hieu qua
dao cac » do cac, sao cac, tao cac
cac ban » cac dan, cac van, can ban
va dao » ca dao
san va » san van, ban va, dan va

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) OR (sach y)) nang ((hoa hoi) OR (hoa hoc)). hieu va dao cac ban thanh san va trien~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) or (sach y)) nang ((hoa hoi) OR (hoa hoc)). hieu va dao cac ban thanh san va trien~".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sach y)) nang ((hoa hoi) OR (hoa hoc)). hieu va dao cac ban thanh san va trien*.