Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
thanh va » thanh van, hanh va, thanh ha
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
xuc va » tuc va, luc va, xac va
va cua » va chua, via cua, ca cua

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

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