Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
ban hanh » ban hang
cam luc » cam xuc, cau luc
lai cua » dai cua, hai cua, lai chau
bai cua » ban cua, dai cua, bai ca
luc ban » duc ban, cuc ban, luc bat
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
mau hoi » cau hoi, mai hoi, mau hop
ky dang » ky nang, ky danh
ve cam » ve cham, ve cac, va cam
mau ho » mau hop, mau co, mau do

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: hoc sach ky dang ((mau hoi) OR (mau ho)). hieu ve cam luc ban hanh ((bai cua) OR (lai cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ky dang ((mau hoi) OR (mau ho)). hieu ve cam luc ban hanh ((bai cua) or (lai cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: hoc sach ky dang ((mau hoi) OR (mau ho)). hieu ve cam luc ban hanh ((bai cua) or (lai cua)) tre*.