Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hieu van » thien van, lieu va, hieu ve
dan hanh » dang hanh, dan khanh, dan thanh
mai hoi » mai khoi, dai hoi, mai doi
lai hoi » dai hoi, lai hoa, lai roi
sach ho » sach hoi, sach ha, sach lo
hieu va » lieu va, hieu qua
nam hoc » nam moc, nam hoi, am hoc
ho nang » thi nang, kha nang, cao nang
tu sach » thu sach, su sach, te sach
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ho nang ((mai hoi) or (lai hoi)). ((hieu van) or (hieu va)) nam hoc dan hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ho nang ((mai hoi) OR (lai hoi)). ((hieu van) OR (hieu va)) nam hoc dan hanh vi cua viet.
• Adding a wildcard symbol may retrieve word variants: tu sach ho nang ((mai hoi) or (lai hoi)). ((hieu van) or (hieu va)) nam hoc dan hanh vi cua viet*.