Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc anh
danh vai » danh sai, danh va, doanh van
cua viet » ca viet, hoa viet, cua vat
hoc cac » hoc cao
mai hoi » mai khoi, dai hoi, mai doi
hieu ve » hieu va, hieu van
cam thu » nam thu, cac thu, ca thu
va danh » va dinh, va dan, va hanh
vai cua » dai cua, hai cua, lai cua
lai hoi » dai hoi, lai hoa, lai roi
v nang » va nang, vu nang, van nang
ve cam » ve cham, ve cac, va cam
thu va » thuc va, thue va, tu va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc sach) OR (hoc cac)) v nang ((mai hoi) or (lai hoi)). hieu ve cam thu va danh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (hoc cac)) v nang ((mai hoi) OR (lai hoi)). hieu ve cam thu va danh vai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc sach) OR (hoc cac)) v nang ((mai hoi) or (lai hoi)). hieu ve cam thu va danh vai cua viet".
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) OR (hoc cac)) v nang ((mai hoi) or (lai hoi)). hieu ve cam thu va danh vai cua viet*.