Perhaps you should try some spelling variations:
cham hoc » cham soc, chat hoc, cham hoi
dinh vai » dinh van, dinh va, dinh tai
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
ty hang » ly hang, ty xang, thi hang
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
dinh vi » dinh ve, dinh viet, dinh tri

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky nang) OR (ty hang)) xa hoi. hieu vu cham hoc va ((dinh vai) OR (dinh vi)) cau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky nang) or (ty hang)) xa hoi. hieu vu cham hoc va ((dinh vai) OR (dinh vi)) cau tren~".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky nang) or (ty hang)) xa hoi. hieu vu cham hoc va ((dinh vai) OR (dinh vi)) cau tren*.