Perhaps you should try some spelling variations:
thanh cac » hanh cac, thanh bac, thanh ca
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
nam thuc » nam thuoc, am thuc, nam thu
nam luc » nang luc, nhan luc, nam duoc
cac cua » cach cua, cac qua, ca cua
bo sach » co sach, hoc sach
sach ky » sac ky, sach y, sach ty
lai hoi » dai hoi, lai hoa, lai roi
mai hoi » mai khoi, dai hoi, mai doi
ky lang » ky nang, ky dang, ky tang
cua tu » cua tuc, cua su, cua cu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach ky lang ((mai hoi) OR (lai hoi)). hieu van ((nam luc) or (nam thuc)) va thanh cac cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach ky lang ((mai hoi) OR (lai hoi)). hieu van ((nam luc) OR (nam thuc)) va thanh cac cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "bo sach ky lang ((mai hoi) OR (lai hoi)). hieu van ((nam luc) or (nam thuc)) va thanh cac cua tu".
• Adding a wildcard symbol may retrieve word variants: bo sach ky lang ((mai hoi) OR (lai hoi)). hieu van ((nam luc) or (nam thuc)) va thanh cac cua tu*.