Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
danh sai » dung sai, danh bat, danh dau
sach thu » sach thue, sach thieu, sach tham
danh vai » danh va, doanh van, dang van
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
sach ty » sach y, sach tu, xach tay
nang o » nang co, nang ho, nang ro
ve am » va am
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: tu ((sach ty) OR (sach thu)) nang o hoi. hieu ve am thuc va ((danh vai) or (danh sai)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach thu)) nang o hoi. hieu ve am thuc va ((danh vai) OR (danh sai)) cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) OR (sach thu)) nang o hoi. hieu ve am thuc va ((danh vai) or (danh sai)) cua triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) OR (sach thu)) nang o hoi. hieu ve am thuc va ((danh vai) or (danh sai)) cua triet*.