Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
hieu van » hieu va, thien van, lieu va
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
te sach » toc sach
hieu ve » hieu va
vai cua » dai cua, hai cua, lai cua
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach thu nang x hoi. ((hieu ve) OR (hieu van)) cac nuoc ((va tinh) or (may tinh)) vai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach thu nang x hoi. ((hieu ve) OR (hieu van)) cac nuoc ((va tinh) OR (may tinh)) vai cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach thu nang x hoi. ((hieu ve) OR (hieu van)) cac nuoc ((va tinh) or (may tinh)) vai cua triet".
• Adding a wildcard symbol may retrieve word variants: te sach thu nang x hoi. ((hieu ve) OR (hieu van)) cac nuoc ((va tinh) or (may tinh)) vai cua triet*.