Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
dinh vai » dinh van, dinh vi, dinh va
nang xa » nang x, lang xa, nang ma
vien da » vien dai, hien dai
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
te sai » te tai, te bai, te lai
sai ky » sac ky
lop va » lap va, hop va
nop va » hop va

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sai ky nang xa hoi. hieu vien da ((lop va) OR (nop va)) dinh vai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sai ky nang xa hoi. hieu vien da ((lop va) OR (nop va)) dinh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: te sai ky nang xa hoi. hieu vien da ((lop va) OR (nop va)) dinh vai cua tre*.