Perhaps you should try some spelling variations:
doanh ban » doanh bat, doanh van, doanh nhan
danh vai » danh sai, danh va, doanh van
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
van cam » van nam, van lam, van cau
ty dang » ky dang, ty hang, ty dong
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, luc va

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 ((ty dang) OR (ty xang)) xa hoi. hieu van cam xuc va ((danh vai) or (doanh ban)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty dang) OR (ty xang)) xa hoi. hieu van cam xuc va ((danh vai) OR (doanh ban)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty dang) OR (ty xang)) xa hoi. hieu van cam xuc va ((danh vai) or (doanh ban)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty dang) OR (ty xang)) xa hoi. hieu van cam xuc va ((danh vai) or (doanh ban)) cua tre*.