Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh tai, hanh van
tu sach » thu sach, su sach, te sach
hanh va » hang va, hanh vi
duc ban » duc tan, duc van, dua ban
cam duc » cam xuc, cao duc, pham duc
van cam » van nam, van lam, van cau
cua tre » cua te, cuu tre, cua triet
y lang » _ lang, tay lang, yen lang
o lang » hoa lang, hoi lang

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 ((y lang) OR (o lang)) xa hoi. hieu van cam duc ban ((hanh vai) or (hanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y lang) OR (o lang)) xa hoi. hieu van cam duc ban ((hanh vai) OR (hanh va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y lang) OR (o lang)) xa hoi. hieu van cam duc ban ((hanh vai) or (hanh va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y lang) OR (o lang)) xa hoi. hieu van cam duc ban ((hanh vai) or (hanh va)) cua tre*.