Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thanh vi » thanh va, thanh ve, nhanh vi
cau duc » cao duc, cau luc, chu duc
van cau » van dau, van hau, van chat
su sach » so sach
hang co » hang cho, hang ca, nang co
vu sach » vu bach, vu khach
cua tre » cua te, cuu tre, cua triet
co hoi » co hoc, co loi
y hang » ly hang, ty hang, yu hang

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 (vu sach)) y hang co hoi. hieu van cau duc va ((thanh vi) or (hanh vi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) y hang co hoi. hieu van cau duc va ((thanh vi) OR (hanh vi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (vu sach)) y hang co hoi. hieu van cau duc va ((thanh vi) or (hanh vi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) OR (vu sach)) y hang co hoi. hieu van cau duc va ((thanh vi) or (hanh vi)) cua tre*.