Perhaps you should try some spelling variations:
vien cac » vien bach, vien da, gian cac
vien dai » hien dai
truc van » truc va, thuc van, truc ban
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
su sach » so sach, vu sach
hanh di » hanh vi, hanh de, hang di
sach 2 » sach y
2 nang » v nang
x hoi » xa hoi, o hoi, x ho
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 2 nang x hoi. hieu ((vien cac) or (vien dai)) truc van hanh di su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach 2 nang x hoi. hieu ((vien cac) OR (vien dai)) truc van hanh di su triet.
• Adding a wildcard symbol may retrieve word variants: su sach 2 nang x hoi. hieu ((vien cac) or (vien dai)) truc van hanh di su triet*.