Perhaps you should try some spelling variations:
thanh dat » thanh san, thanh hai, thanh van
doc sach » hoc sach, toc sach, nuoc sach
xa thanh » va thanh, ha thanh, ta thanh
su triet » su viet, su tien, ve triet
hieu va » lieu va, hieu qua
cac toc » cac toi, cac nuoc, cac thoi
cac tuc » cac tu, cac tac, cac nuoc
ca hoi » cau hoi, cua hoi, xa hoi
dat su » sat 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 ((thi hanh) OR (thi thanh)) ca hoi. hieu va ((cac tuc) or (cac toc)) xa thanh dat su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ((thi hanh) OR (thi thanh)) ca hoi. hieu va ((cac tuc) OR (cac toc)) xa thanh dat su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ((thi hanh) OR (thi thanh)) ca hoi. hieu va ((cac tuc) or (cac toc)) xa thanh dat su triet".
• Adding a wildcard symbol may retrieve word variants: doc sach ((thi hanh) OR (thi thanh)) ca hoi. hieu va ((cac tuc) or (cac toc)) xa thanh dat su triet*.