Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
doc sach » hoc sach, nuoc sach, dac sac
xa thanh » va thanh, ha thanh, ta thanh
su triet » su viet, su tien, ve triet
thi hanh » thi thanh
toc sach » hoc sach, thuoc sach, nuoc sach
hanh ca » hanh cac, hanh cat, hanh cua
cac tuc » cac tu, cac tac, cac nuoc
cac toc » cac toi, cac nuoc, cac thoi
hieu va » lieu va, hieu qua
ca hoi » cau hoi, cua hoi, xa hoi
dai su » dai sua, dai so, dan su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc sach) OR (toc sach)) thi hanh ca hoi. hieu va ((cac tuc) or (cac toc)) xa thanh dai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc sach) OR (toc sach)) thi hanh ca hoi. hieu va ((cac tuc) OR (cac toc)) xa thanh dai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc sach) OR (toc sach)) thi hanh ca hoi. hieu va ((cac tuc) or (cac toc)) xa thanh dai su triet".
• Adding a wildcard symbol may retrieve word variants: ((doc sach) OR (toc sach)) thi hanh ca hoi. hieu va ((cac tuc) or (cac toc)) xa thanh dai su triet*.