Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
su triet » su viet, su tien, ve triet
te sach » toc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
hieu ve » hieu va, hieu van
ve bac » ve bao, ve cac, ve ban
bo van » vo van, so van, do van
tai su » tai so, tai tu, lai su
x hoi » o hoi, x ho
5 hoi » o hoi

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 ty nang ((((x hoi) or (5 hoi))) or (xa hoi)). hieu ve bac bo van hanh tai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang ((((x hoi) OR (5 hoi))) OR (xa hoi)). hieu ve bac bo van hanh tai su triet.
• Adding a wildcard symbol may retrieve word variants: te sach ty nang ((((x hoi) or (5 hoi))) or (xa hoi)). hieu ve bac bo van hanh tai su triet*.