Perhaps you should try some spelling variations:
su sach » so sach, vu sach
co sach » bo sach, cuon sach, hoc sach
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
luc va » duc va, tuc va
loc va » hoc va
vi cua » vai cua, di cua

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) or (co sach)) ky nang cao hoi. hieu va cam ((luc va) or (loc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (co sach)) ky nang cao hoi. hieu va cam ((luc va) OR (loc va)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (co sach)) ky nang cao hoi. hieu va cam ((luc va) or (loc va)) hanh vi cua tre*.