Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
ly quang » le quang, vu quang
cam thuc » am thuc, nam thuc, cam thu
hang di » hang doi, hang vi, hang dien
va hang » van hang, va nang, va lang
thuc va » thuc vat, thuc dan, thuc day
co sach » bo sach, cuon sach, hoc sach
hieu va » lieu va
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: co sach ((ly hang) OR (ly quang)) xa hoi. ((hieu va) or (hieu qua)) cam thuc va hang di su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ((ly hang) OR (ly quang)) xa hoi. ((hieu va) OR (hieu qua)) cam thuc va hang di su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "co sach ((ly hang) OR (ly quang)) xa hoi. ((hieu va) or (hieu qua)) cam thuc va hang di su triet".
• Adding a wildcard symbol may retrieve word variants: co sach ((ly hang) OR (ly quang)) xa hoi. ((hieu va) or (hieu qua)) cam thuc va hang di su triet*.