Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hanh tai » thanh tai, hang tai, han tai
nam thuc » nam thuoc, am thuc, nam thu
thi hang » thi hanh, thi hong, thi thanh
thi nang » thi cong, ki nang, thi hanh
hoc doi » hoc dai, hoc noi, hoc moi
hieu le » hieu ve, hieu he, hieu ly
va hanh » van hanh, va thanh, va danh
te sach » toc sach
tai va » thai va, mai va, tri va
nuoc » quoc, duoc, ngoc

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 ((thi hang) OR (thi nang)) hoc doi. hieu le ((nam thuc) or (nha nuoc)) va hanh tai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((thi hang) OR (thi nang)) hoc doi. hieu le ((nam thuc) OR (nha nuoc)) va hanh tai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((thi hang) OR (thi nang)) hoc doi. hieu le ((nam thuc) or (nha nuoc)) va hanh tai va triet".
• Adding a wildcard symbol may retrieve word variants: te sach ((thi hang) OR (thi nang)) hoc doi. hieu le ((nam thuc) or (nha nuoc)) va hanh tai va triet*.