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

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