Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
ly quang » le quang, vu quang
co sach » bo sach, cuon sach, hoc sach
cac bac » cac bai, cac ban, cac cach
tai duc » tai cuc, mai duc, tai du
cac tuc » cac toc, cac tu, cac tac
hieu va » lieu va, hieu qua
duc tre » duoc tren, duc tien

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 va ((cac tuc) or (cac bac)) van 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 va ((cac tuc) OR (cac bac)) van hanh tai duc tre.
• Adding a wildcard symbol may retrieve word variants: co sach ((ly hang) or (ly quang)) xa hoi. hieu va ((cac tuc) or (cac bac)) van hanh tai duc tre*.