Perhaps you should try some spelling variations:
dua tren » dung tren
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cuu tre, cua triet
xua ban » xuat ban, cua ban, qua ban
hanh ve » hanh vi, hanh va, hanh kem
nam xua » nam cua, nam mua, nam qua
sac ky » cac ky, sai ky
anh ve » anh va, anh viet, thanh ve
nang o » nang co, nang ho, nang ro
tu sac » tu sach, tu cac, tu san
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: tu sac ky nang o hoi. hieu van nam xua ban ((anh ve) OR (hanh ve)) ((dua tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang o hoi. hieu van nam xua ban ((anh ve) OR (hanh ve)) ((dua tren) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang o hoi. hieu van nam xua ban ((anh ve) OR (hanh ve)) ((dua tren) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang o hoi. hieu van nam xua ban ((anh ve) OR (hanh ve)) ((dua tren) or (cua tre))*.