Perhaps you should try some spelling variations:
toc sac » toc sach, toc san, hoc sach
hanh ve » hanh vi, hanh va, hanh kem
dao van » dang van
su viet » so viet
nang xa » nang x, lang xa, nang ma
sac ky » cac ky, sai ky
do van » vo van, so van
ve cac » va cac, vien cac
ve ca » ve cai, ve cau, ve cua
ve su » va su

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: toc sac ky nang xa hoi. hieu ((ve ca) OR (ve cac)) ((dao van) OR (do van)) hanh ve su viet~.
• Adding a wildcard symbol may retrieve word variants: toc sac ky nang xa hoi. hieu ((ve ca) or (ve cac)) ((dao van) or (do van)) hanh ve su viet*.