Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
van thanh » van tuan
su sach » so sach, vu sach
cao hoi » cau hoi, cao hoc, tao hoi
luc van » luoc van, luu van, duc van
ban hai » ban thai, bang hai, van hai
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
co hoi » co hoc, co loi

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 v nang ((cao hoi) OR (co hoi)). hieu ((van thanh) or (ban thanh)) luc van ban hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v nang ((cao hoi) OR (co hoi)). hieu ((van thanh) OR (ban thanh)) luc van ban hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v nang ((cao hoi) OR (co hoi)). hieu ((van thanh) or (ban thanh)) luc van ban hai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach v nang ((cao hoi) OR (co hoi)). hieu ((van thanh) or (ban thanh)) luc van ban hai cua tre*.