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