Perhaps you should try some spelling variations:
cac khoi » cac thoi, cac khoan, cach thoi
hanh vai » hanh vi, hanh va, hanh tai
cam thuc » am thuc, nam thuc, cam thu
cua viet » ca viet, hoa viet, cua vat
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
vai cua » dai cua, hai cua, lai cua
so sach » so sanh, bo sach, co sach
sach v » sach va, sach y, sach 2
ve cam » ve cham, ve cac, va cam
v nang » va nang, vu nang, van nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach v nang ((mai hoi) or (cac khoi)). hieu ve cam thuc va hanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach v nang ((mai hoi) OR (cac khoi)). hieu ve cam thuc va hanh vai cua viet.
• Adding a wildcard symbol may retrieve word variants: so sach v nang ((mai hoi) or (cac khoi)). hieu ve cam thuc va hanh vai cua viet*.