Perhaps you should try some spelling variations:
doanh va » doanh tai, doanh cua, hanh va
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
cham tu » pham tu, cam tu, chai tu
tu van » tu 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 y ((nang xa) or (lang xa)) hoi. hieu ve cham tu van ((doanh va) OR (doan va)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang xa) OR (lang xa)) hoi. hieu ve cham tu van ((doanh va) OR (doan va)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang xa) or (lang xa)) hoi. hieu ve cham tu van ((doanh va) OR (doan va)) su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang xa) or (lang xa)) hoi. hieu ve cham tu van ((doanh va) OR (doan va)) su triet*.