Perhaps you should try some spelling variations:
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
du cua » duy cua, dau cua, dum cua
va cau » van cau, va cac, va dau
ve cau » ke cau, ve cac, le cau
ang xa » lang xa, mang xa, dang xay
ty ang » ty xang, ty hang, ty anh
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty ang xa hoi. hieu ((ve cau) OR (va cau)) luc ((van hanh) or (ban hanh)) du cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty ang xa hoi. hieu ((ve cau) OR (va cau)) luc ((van hanh) OR (ban hanh)) du cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty ang xa hoi. hieu ((ve cau) OR (va cau)) luc ((van hanh) or (ban hanh)) du cua te".
• Adding a wildcard symbol may retrieve word variants: so sach ty ang xa hoi. hieu ((ve cau) OR (va cau)) luc ((van hanh) or (ban hanh)) du cua te*.