Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
thu sach » tu sach, thuat sach, thuoc sach
sach tru » sach truc, sach thu, sach tu
tru nang » tra nang, tri nang, truc nano
vien cao » vien cac, vien dai, vien da
cao nuoc » cap nuoc, cac nuoc, cao ngoc
mai hoi » mai khoi, dai hoi, mai doi
lai hoi » dai hoi, lai hoa, lai roi
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach tru nang ((mai hoi) or (lai hoi)). hieu vien cao nuoc va hanh di cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach tru nang ((mai hoi) OR (lai hoi)). hieu vien cao nuoc va hanh di cua vat.
• Adding a wildcard symbol may retrieve word variants: thu sach tru nang ((mai hoi) or (lai hoi)). hieu vien cao nuoc va hanh di cua vat*.