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
luc van » luoc van, luu van, duc van
tu sach » thu sach, te sach, tu cach
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
su sach » so sach, vu sach
cac luc » cau luc, coc luc, cac nuoc
2 lang » 22 lang, o lang, _ lang

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)) 2 lang xa hoi. hieu va cac luc van ((hanh lai) OR (hanh tai)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) 2 lang xa hoi. hieu va cac luc van ((hanh lai) OR (hanh tai)) cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) 2 lang xa hoi. hieu va cac luc van ((hanh lai) OR (hanh tai)) cua triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) 2 lang xa hoi. hieu va cac luc van ((hanh lai) OR (hanh tai)) cua triet*.