Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
cam thuc » am thuc, nam thuc, cam thu
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
sac ky » cac ky, sai ky
ve cam » ve cham, ve cac, va cam
vi cua » vai cua
di cua » dai cua, doi cua, de cua
su sac » su sach, su cac, su xac

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 ((nang xa) OR (nang ma)) hoi. hieu ve cam thuc van hanh ((vi cua) or (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky ((nang xa) OR (nang ma)) hoi. hieu ve cam thuc van hanh ((vi cua) OR (di cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky ((nang xa) OR (nang ma)) hoi. hieu ve cam thuc van hanh ((vi cua) or (di cua)) tre*".