Perhaps you should try some spelling variations:
thuc van » thuc vat, thuc dan, thuc va
van hanh » van thanh, ban hanh, van anh
cam thuc » am thuc, nam thuc, cam thu
ky sang » ky nang, ky dang, ky tang
vai cua » dai cua, hai cua, lai cua
hieu ve » hieu va, hieu van
di cua » dai cua, doi cua, de cua
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky
ma hoi » mai hoi, ma hoa, me hoi
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: su sac ky sang ((ma hoi) OR (xa hoi)). hieu ve cam thuc van hanh ((vai cua) or (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky sang ((ma hoi) OR (xa hoi)). hieu ve cam thuc van hanh ((vai cua) OR (di cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky sang ((ma hoi) OR (xa hoi)). hieu ve cam thuc van hanh ((vai cua) or (di cua)) tre*".