Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
va trien » va truyen, va thiet, va tuyen
thanh vu » thanh va, thanh ve, thanh tu
cam thuc » am thuc, nam thuc, can thuc
hieu van » hieu va, thien van, lieu va
lang van » dang van, tang van, hoang van
cam thu » nam thu, cac thu, ca thu
lang xa » lang ha, dang xay
su sach » so sach, vu sach
sach o » sach lo, sac o, sach y
vu va » vu van, tu va, su va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach o ((lang xa) or (lang van)) hoi. hieu van ((cam thuc) OR (cam thu)) ban thanh vu va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach o ((lang xa) OR (lang van)) hoi. hieu van ((cam thuc) OR (cam thu)) ban thanh vu va trien*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach o ((lang xa) or (lang van)) hoi. hieu van ((cam thuc) OR (cam thu)) ban thanh vu va trien*".