Perhaps you should try some spelling variations:
dan hanh » dang hanh, dan khanh, dan thanh
vu khach » vu khanh, vu khac, vay khach
hieu ve » hieu van
hieu va » lieu va, hieu qua
nam hoc » nam moc, nam hoi, am hoc
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
vi cuu » vi luu, vinh cuu
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu khach y nang ((o hoi) or (x ho)). ((hieu ve) or (hieu va)) nam hoc dan hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu khach y nang ((o hoi) OR (x ho)). ((hieu ve) OR (hieu va)) nam hoc dan hanh vi cuu tre.
• Adding a wildcard symbol may retrieve word variants: vu khach y nang ((o hoi) or (x ho)). ((hieu ve) or (hieu va)) nam hoc dan hanh vi cuu tre*.