Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
te sach » toc sach
hieu ve » hieu va, hieu van
vai cua » dai cua, hai cua, bai cua
lai cua » dai cua, hai cua, lai chau
ve cac » va cac, vien cac
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 cac nuoc ((va tinh) or (may tinh)) ((vai cua) OR (lai cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach thu nang x hoi. hieu ve cac nuoc ((va tinh) OR (may tinh)) ((vai cua) OR (lai cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach thu nang x hoi. hieu ve cac nuoc ((va tinh) or (may tinh)) ((vai cua) OR (lai cua)) triet".
• Adding a wildcard symbol may retrieve word variants: te sach thu nang x hoi. hieu ve cac nuoc ((va tinh) or (may tinh)) ((vai cua) OR (lai cua)) triet*.