Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
toc sach » hoc sach, doc sach, thuoc sach
vien dai » hien dai
dinh vai » dinh van, dinh vi, dinh va
vai cua » dai cua, hai cua, lai cua
nang xa » nang x, lang xa, nang ma
lo van » le van, vo van, so van
cua te » cua tu
lo va » lao va, ly va, le va

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

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