Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
hanh va » hang va, hanh vi
cam duc » cam xuc, cao duc, pham duc
van cam » van nam, van lam, van cau
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
lai hoi » dai hoi, lai hoa, lai roi
mai hoi » mai khoi, dai hoi, mai doi
ky lang » ky nang, ky dang, ky tang
cuu tre » cua tre, cau tren, cau treo

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 ky lang ((mai hoi) or (lai hoi)). hieu van cam duc va ((hanh tai) or (hanh va)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang ((mai hoi) OR (lai hoi)). hieu van cam duc va ((hanh tai) OR (hanh va)) cuu tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang ((mai hoi) or (lai hoi)). hieu van cam duc va ((hanh tai) or (hanh va)) cuu tre*.