Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
thanh vi » hanh vi, thanh va, thanh ve
nam xuc » cam xuc, nam xua, nam thuc
cua tre » cua te, cuu tre, dua tren
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky
xuc va » duc va, tuc va, luc va
x hoi » o hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky nang ((x hoi) or (xa hoi)). hieu van nam xuc va thanh vi ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky nang ((x hoi) OR (xa hoi)). hieu van nam xuc va thanh vi ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky nang ((x hoi) or (xa hoi)). hieu van nam xuc va thanh vi ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: su sac ky nang ((x hoi) or (xa hoi)). hieu van nam xuc va thanh vi ((cua tre) OR (cua triet))*.