Perhaps you should try some spelling variations:
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
cam thuc » am thuc, nam thuc, cam thu
tu sach » thu sach, su sach, tu cach
hieu ve » hieu va, hieu van
hang xa » hoang xa, hang va, hang ca
ty hang » ly hang, ty xang, thi hang
te sach » toc sach
ve cam » ve cham, ve cac, va cam
vi cua » vai cua, di cua
cua te » cua tu

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ty hang xa hoi. hieu ve cam thuc ((van hanh) OR (ban hanh)) vi cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (te sach)) ty hang xa hoi. hieu ve cam thuc ((van hanh) or (ban hanh)) vi cua te~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (te sach)) ty hang xa hoi. hieu ve cam thuc ((van hanh) or (ban hanh)) vi cua te*.