Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hanh tai » thanh tai, hang tai, han tai
hanh lai » hanh lam, thanh lap, thanh loi
sach ky » sac ky, sach ty, sach kem
hieu ve » hieu va, hieu van
cac bo » bac bo, cac co
bo van » vo van, so van, do van
nang o » nang co, nang ho, nang ro
ve cac » va cac, vien cac
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 ky) OR (sach y)) nang o hoi. hieu ve cac bo van ((hanh lai) or (hanh tai)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang o hoi. hieu ve cac bo van ((hanh lai) OR (hanh tai)) cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sach y)) nang o hoi. hieu ve cac bo van ((hanh lai) or (hanh tai)) cua triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sach y)) nang o hoi. hieu ve cac bo van ((hanh lai) or (hanh tai)) cua triet*.