Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
dang van » hoang van, hang va
vien cac » vien bach, vien dai, vien da
lang xa » lang ha, dang xay, lang van
cac toc » cac toi, cac nuoc, cac thoi
xa dong » ha dong, van dong, lao dong
da nang » cam nang, kha nang, cao nang
sac ky » cac ky, sai ky
su sac » su sach, su cac, su xac
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: su sac ky ((lang xa) or (dang van)) hoi. hieu vien cac toc ((xa dong) or (da nang)) hoi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky ((lang xa) OR (dang van)) hoi. hieu vien cac toc ((xa dong) OR (da nang)) hoi va thiet.
• Adding a wildcard symbol may retrieve word variants: su sac ky ((lang xa) or (dang van)) hoi. hieu vien cac toc ((xa dong) or (da nang)) hoi va thiet*.