Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
hanh doi » thanh doi, hanh noi, hang doi
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
te cac » ve cac, te cao, de cac
luc va » duc va, tuc va
loc va » hoc va
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te cac) OR (tu cac)) ky nang x hoi. hieu vien cac ((luc va) or (loc va)) hanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te cac) OR (tu cac)) ky nang x hoi. hieu vien cac ((luc va) OR (loc va)) hanh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te cac) OR (tu cac)) ky nang x hoi. hieu vien cac ((luc va) or (loc va)) hanh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te cac) OR (tu cac)) ky nang x hoi. hieu vien cac ((luc va) or (loc va)) hanh doi cua tre*.