Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
dang xay » dang van, van xay
danh vai » danh sai, danh va, dang van
tu sach » thu sach, su sach, te sach
cao duc » dao duc, cao suc, giao duc
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
va cao » va cac, va co, va dao

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 ky ((dang xay) or (hang va)) hoi. hieu va cao duc va ((danh vai) or (doanh van)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((dang xay) OR (hang va)) hoi. hieu va cao duc va ((danh vai) OR (doanh van)) cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((dang xay) or (hang va)) hoi. hieu va cao duc va ((danh vai) or (doanh van)) cua tre*.