Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
mai khoi » mai khoa, tai khoa, cac khoi
thanh va » thanh van, hanh va, thanh ha
thanh vi » hanh vi, thanh ve, nhanh vi
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
van hac » van hoc, van ha, van hai
hac dat » hoc dat, tac dat, hoach dat
dat ban » bat ban, da ban, day ban
mai hoi » dai hoi, lai hoi, mai doi
ty nang » ky nang, ty xang, ty hang

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 ty nang ((mai hoi) OR (mai khoi)). hieu van hac dat ban ((thanh vi) or (thanh va)) cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang ((mai hoi) OR (mai khoi)). hieu van hac dat ban ((thanh vi) OR (thanh va)) cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty nang ((mai hoi) OR (mai khoi)). hieu van hac dat ban ((thanh vi) or (thanh va)) cua vat".
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang ((mai hoi) OR (mai khoi)). hieu van hac dat ban ((thanh vi) or (thanh va)) cua vat*.