Perhaps you should try some spelling variations:
van khanh » van thanh, van hanh, van anh
su triet » su viet, su tien, ve triet
khanh di » khanh bui, khanh duy, thanh doi
truc van » truc va, thuc van, truc ban
vien dai » hien dai
su sach » so sach, vu sach
va nang » van nang, da nang, cam nang
v nang » vu nang, van nang, voi nang
di su » doi su, ki su, da su

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((v nang) OR (va nang)) xa hoi. hieu ((vien bach) or (vien dai)) truc van khanh di su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((v nang) OR (va nang)) xa hoi. hieu ((vien bach) OR (vien dai)) truc van khanh di su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((v nang) OR (va nang)) xa hoi. hieu ((vien bach) or (vien dai)) truc van khanh di su triet".
• Adding a wildcard symbol may retrieve word variants: su sach ((v nang) OR (va nang)) xa hoi. hieu ((vien bach) or (vien dai)) truc van khanh di su triet*.