Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
va triet » va thiet, va trien, ve triet
ky lang » ky nang, ky dang, ky tang
lang ha » long ha
hieu va » lieu va, hieu qua
cho hoc » khoa hoc
su xac » pu xac, su cac
xac ky » cac ky, sac ky, bac ky
ha hoi » hoa hoi, ha noi, xa hoi
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: su xac ky lang ha hoi. hieu va ((co hoc) or (cho hoc)) van hanh tai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su xac ky lang ha hoi. hieu va ((co hoc) OR (cho hoc)) van hanh tai va triet.
• Adding a wildcard symbol may retrieve word variants: su xac ky lang ha hoi. hieu va ((co hoc) or (cho hoc)) van hanh tai va triet*.