Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
day thanh » dao thanh, dat thanh, da thanh
day hanh » day nhanh, dao hanh, day manh
cam thuc » am thuc, nam thuc, cam thu
hieu ve » hieu va, hieu van
co sach » bo sach, cuon sach, hoc sach
su sach » so sach, vu sach
ve cam » ve cham, ve cac, va cam
nang o » nang co, nang ho, nang ro
vi cua » vai cua, di cua
o hoi » co hoi, o hoc, o hai

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 (co sach)) ky nang o hoi. hieu ve cam thuc ((day hanh) OR (day thanh)) vi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (co sach)) ky nang o hoi. hieu ve cam thuc ((day hanh) OR (day thanh)) vi cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (co sach)) ky nang o hoi. hieu ve cam thuc ((day hanh) OR (day thanh)) vi cua triet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (co sach)) ky nang o hoi. hieu ve cam thuc ((day hanh) OR (day thanh)) vi cua triet*.