Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
vat hanh » vat thanh, van hanh, va hanh
cam thuc » am thuc, nam thuc, cam thu
hanh di » hanh vi, hanh de, hang di
hieu ve » hieu va, hieu van
su sach » so sach
nang xa » lang xa, nang ma, mang xa
vu sach » vu bach, vu khach
ve cam » ve cham, ve cac, va cam
di su » doi su, ki su, da su

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) or (vu sach)) v ((nang xa) or (nang x)) hoi. hieu ve cam thuc vat hanh di su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) v ((nang xa) OR (nang x)) hoi. hieu ve cam thuc vat hanh di su triet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) v ((nang xa) or (nang x)) hoi. hieu ve cam thuc vat hanh di su triet*.