Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dang hai » dang khai, hang hai, dung hai
danh hai » lanh hai, manh hai, danh hau
cua viet » ca viet, hoa viet, cua vat
lai hoi » dai hoi, lai hoa, lai roi
mai hoi » mai khoi, dai hoi, mai doi
hieu ve » hieu va, hieu van
cam thu » nam thu, cac thu, ca thu
sach v » sach va, sach y, sach 2
thu va » thuc va, thue va, tu va
v nang » va nang, vu nang, van nang
ve cam » ve cham, ve cac, va cam

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