Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
nang o » nang co, nang ho, nang ro
ve cac » vien cac
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
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: ((tu sach) OR (su sach)) ky nang o hoi. hieu ((ve cac) or (va cac)) tu va dan vi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang o hoi. hieu ((ve cac) OR (va cac)) tu va dan vi cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) ky nang o hoi. hieu ((ve cac) or (va cac)) tu va dan vi cua triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) ky nang o hoi. hieu ((ve cac) or (va cac)) tu va dan vi cua triet*.