Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hanh hoi » hanh thoi, hanh noi, hanh hoa
hoi cua » hoi chuc
sach ty » sach y, sach tu, sach thu
vu cham » va cham, vu kham, tu cham
hieu vu » hieu va, hieu ve, hieu su
cao hoc » co hoc, cho hoc, chat hoc
cao hoi » cau hoi, co hoi, tao hoi
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
lao va » tao va, cao va, bao va
lo va » lo van, ly va, le va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ty nang ((cao hoi) or (cao hoc)). hieu vu cham ((lo va) OR (lao va)) hanh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ty nang ((cao hoi) OR (cao hoc)). hieu vu cham ((lo va) OR (lao va)) hanh hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ty nang ((cao hoi) or (cao hoc)). hieu vu cham ((lo va) OR (lao va)) hanh hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ty nang ((cao hoi) or (cao hoc)). hieu vu cham ((lo va) OR (lao va)) hanh hoi cua tre*.