Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
su triet » su viet, su tien, ve triet
thanh di » thanh doi, thanh de, thanh do
thuc van » thuc vat, thuc dan, thuc va
cam thuc » am thuc, nam thuc, cam thu
hieu van » hieu va, thien van, lieu va
van cam » van nam, van lam, van cau
su sach » so sach
vu sach » vu bach, vu khach
nang xa » lang xa, nang ma, mang xa
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 van cam thuc van thanh 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 van cam thuc van thanh di su triet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) v ((nang xa) or (nang x)) hoi. hieu van cam thuc van thanh di su triet*.