Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
hanh vai » hanh vi, hanh tai, hanh van
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
cac toc » cac toi, cac nuoc, cac thoi
hanh va » hang va, hanh vi
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky dang xa hoi. hieu vien ((cac toc) or (dat nuoc)) van ((hanh vai) OR (hanh va)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky dang xa hoi. hieu vien ((cac toc) OR (dat nuoc)) van ((hanh vai) OR (hanh va)) va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky dang xa hoi. hieu vien ((cac toc) or (dat nuoc)) van ((hanh vai) OR (hanh va)) va thiet".
• Adding a wildcard symbol may retrieve word variants: te sac ky dang xa hoi. hieu vien ((cac toc) or (dat nuoc)) van ((hanh vai) OR (hanh va)) va thiet*.