Perhaps you should try some spelling variations:
ban doanh » van doanh, san doanh, toan doanh
ban danh » ban hanh, ban dan, van danh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
lang ha » long ha
ky lang » ky nang, ky dang, ky tang
ve cai » va cai, ve cac, ve tai
ha hoi » hoa hoi, ha noi, xa hoi
vi cua » vai cua, di cua
ve ca » ve cac, ve cau, ve 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 ky lang ha hoi. hieu ((ve ca) or (ve cai)) cua ((ban danh) OR (ban doanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang ha hoi. hieu ((ve ca) OR (ve cai)) cua ((ban danh) OR (ban doanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky lang ha hoi. hieu ((ve ca) or (ve cai)) cua ((ban danh) OR (ban doanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang ha hoi. hieu ((ve ca) or (ve cai)) cua ((ban danh) OR (ban doanh)) vi cua tre*.