Perhaps you should try some spelling variations:
van doanh » toan doanh, van dong, van thanh
doanh va » doan va, doanh tai, doanh cua
tu sach » thu sach, su sach, te sach
van cau » van dau, van hau, van chat
sach ty » sach y, sach tu, sach thu
van cam » van nam, van lam, van dam
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, me hoi
lo van » le van, vo van, so van
va cua » va chua, via cua, ca 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 ty nang ((ma hoi) OR (ma hoa)). hieu ((van cam) or (van cau)) lo van doanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((ma hoi) OR (ma hoa)). hieu ((van cam) OR (van cau)) lo van doanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((ma hoi) OR (ma hoa)). hieu ((van cam) or (van cau)) lo van doanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((ma hoi) OR (ma hoa)). hieu ((van cam) or (van cau)) lo van doanh va cua tre*.