Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
thu san » thuy san, thu ban, phu san
van cam » van nam, van lam, van cau
cam duc » cam xuc, cao duc, pham duc
san ky » sang ky, van ky, dan ky
cua cu » cua chu, cua cau, cua co
cua su » qua su
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: thu san ky nang ((x ho) or (o hoi)). hieu van cam duc va thanh tai ((cua cu) OR (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu san ky nang ((x ho) OR (o hoi)). hieu van cam duc va thanh tai ((cua cu) OR (cua su)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu san ky nang ((x ho) or (o hoi)). hieu van cam duc va thanh tai ((cua cu) OR (cua su))".
• Adding a wildcard symbol may retrieve word variants: thu san ky nang ((x ho) or (o hoi)). hieu van cam duc va thanh tai ((cua cu) OR (cua su))*.