Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
cham duc » cham soc, pham duy, phan duc
te sach » toc sach
hieu ve » hieu va, hieu van
tu nang » tru nang, tu nong, tu nano
tai va » thai va, mai va, tri va

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 ((tu nang) or (truc nano)) xa hoi. hieu ve ((cham duc) OR (pham duc)) van hanh tai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((tu nang) OR (truc nano)) xa hoi. hieu ve ((cham duc) OR (pham duc)) van hanh tai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((tu nang) or (truc nano)) xa hoi. hieu ve ((cham duc) OR (pham duc)) van hanh tai va triet".
• Adding a wildcard symbol may retrieve word variants: te sach ((tu nang) or (truc nano)) xa hoi. hieu ve ((cham duc) OR (pham duc)) van hanh tai va triet*.