Perhaps you should try some spelling variations:
ve triet » va trien, su triet
hanh dai » hanh tai, hanh dao, vanh dai
van hanh » van thanh, ban hanh, van anh
sach thu » sach thue, sach thieu, sach tham
pham duy » pham duc
duy van » duy vat, dung van
ve pham » vi pham, v pham, ve phan
hieu ve » hieu va, hieu van
sach ty » sach y, sach tu, xach tay
dai ve » dap ve, dau ve, dai va
x hoi » xa hoi, x ho, 5 hoi
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 ty) or (sach thu)) nang ((x hoi) OR (o hoi)). hieu ve pham duy van hanh dai ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach thu)) nang ((x hoi) OR (o hoi)). hieu ve pham duy van hanh dai ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) or (sach thu)) nang ((x hoi) OR (o hoi)). hieu ve pham duy van hanh dai ve triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sach thu)) nang ((x hoi) OR (o hoi)). hieu ve pham duy van hanh dai ve triet*.