Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
nuoc luan » luc luan
hieu van » hieu va, thien van, lieu va
quoc lan » quoc ban, quoc quan, quoc danh
tay lang » tai lang, tay tang, tay quang
van lam » van nam
benh ve » benh va, benh vien, benh viem
te sach » toc sach
y lang » o lang, _ lang, yen lang
ve cua » le cua, de cua, te cua

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 ((y lang) or (tay lang)) xa hoi. hieu van lam ((quoc lan) OR (nuoc luan)) benh ve cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((y lang) OR (tay lang)) xa hoi. hieu van lam ((quoc lan) OR (nuoc luan)) benh ve cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((y lang) or (tay lang)) xa hoi. hieu van lam ((quoc lan) OR (nuoc luan)) benh ve cua triet".
• Adding a wildcard symbol may retrieve word variants: te sach ((y lang) or (tay lang)) xa hoi. hieu van lam ((quoc lan) OR (nuoc luan)) benh ve cua triet*.