Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
nang mai » nang ma, nang tai, lang mai
cam thuc » am thuc, nam thuc, cam thu
thuc ban » thuoc ban, thuc dan, thu ban
so sach » so sanh, bo sach, co sach
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
vai cua » dai cua, hai cua, lai cua
di cua » dai cua, doi cua, de cua
so sac » so dac
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sac) OR (so sach)) ky nang mai hoi. hieu ve cam thuc ban thanh ((vai cua) or (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sac) OR (so sach)) ky nang mai hoi. hieu ve cam thuc ban thanh ((vai cua) OR (di cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sac) OR (so sach)) ky nang mai hoi. hieu ve cam thuc ban thanh ((vai cua) or (di cua)) tre*".