Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
tru nang » tra nang, tri nang, truc nano
thanh va » thanh van, hanh va, thanh ha
tu sach » thu sach, su sach, te sach
tu nang » tu nong, tu nano, tu lang
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 ((tu nang) OR (tru 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 ((tu nang) OR (tru 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 ((tu nang) OR (tru 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 ((tu nang) OR (tru nang)) xa hoi. hieu vien bach ((xuc va) or (duc va)) thanh va cua tre*.