Perhaps you should try some spelling variations:
ban doanh » van doanh, san doanh, ban danh
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
bai cuu » bai cua, bai cung
cua tre » cua te, cuu tre, cua triet
sach o » sach lo, sac o, sach y
o lang » hoa lang, hoi lang
vi cua » vai cua, di cua

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 o lang xa hoi. hieu va bai cuu ((ban doanh) or (ban hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach o lang xa hoi. hieu va bai cuu ((ban doanh) OR (ban hanh)) vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach o lang xa hoi. hieu va bai cuu ((ban doanh) or (ban hanh)) vi cua tre*.