Perhaps you should try some spelling variations:
hieu suat » hieu luat, hieu qua
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
soc van » hoc van, oc van, sac van
van anh » van thanh, tuan anh, van minh
anh te » anh tu, anh ta, anh ve
te cua » tue cua, le cua, de cua

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 xa hoi. ((hieu va) OR (hieu suat)) cham soc van anh te cua viet~.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. ((hieu va) or (hieu suat)) cham soc van anh te cua viet*.