Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
van cam » van nam, van lam, van cau
duc ban » dua ban, duc man, duc manh
duc van » duc va, duc manh, duc phan
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

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