Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
danh vai » danh sai, danh va, dang van
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cam duc » cam xuc, cao duc, pham duc
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va
lang xa » lang ha, dang xay, lang van
ty lang » tay lang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet

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