Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
ly quang » le quang, vu quang
co sach » bo sach, cuon sach, hoc sach
cac tuc » cac tu, cac tac, cac nuoc
tai duc » tai cuc, mai duc, tai du
va hanh » van hanh, va thanh, va danh
cac toc » cac toi, cac nuoc, cac thoi
duc tre » duoc tren, duc tien
hieu ve » hieu va, hieu van

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

• Performing a fuzzy search may retrieve terms with similar spellings: co sach ((ly hang) or (ly quang)) xa hoi. hieu ve ((cac tuc) OR (cac toc)) va hanh tai duc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ((ly hang) OR (ly quang)) xa hoi. hieu ve ((cac tuc) OR (cac toc)) va hanh tai duc tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "co sach ((ly hang) or (ly quang)) xa hoi. hieu ve ((cac tuc) OR (cac toc)) va hanh tai duc tre*".