Perhaps you should try some spelling variations:
hay dong » ha dong, day dong, hay song
huy dong » ha dong
hieu van » hieu va, thien van, lieu va
chua tre » chua tri, cua tre, chua trieu
so sach » so sanh, bo sach, co sach
van lam » van nam
vi chua » va chua, vi khuan, chi chua
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ((hay dong) or (huy dong)) xa hoi. hieu van lam ((tuc va) or (duc va)) hanh vi chua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((hay dong) OR (huy dong)) xa hoi. hieu van lam ((tuc va) OR (duc va)) hanh vi chua tre.
• Adding a wildcard symbol may retrieve word variants: so sach ((hay dong) or (huy dong)) xa hoi. hieu van lam ((tuc va) or (duc va)) hanh vi chua tre*.