Perhaps you should try some spelling variations:
nghiem so » nghiem son, nghiep so, nghiem do
thu sach » tu sach, thuat sach, thuoc sach
bai nghe » thai nghe, van nghe, nam nghe
hoach ha » hoach xay, hoach hoi, hoach su
hoach va » hoach xay, hanh va, doanh va
te sach » toc sach
nghe du » nghe duc, nghe xu, nghe di
du hoc » tu hoc, duoc hoc
so hoc » co hoc, mo hoc, so hoa

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 (thu sach)) bai nghe du hoc ) or ( thu ((hoach ha) or (hoach va)) nghiem so hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((te sach) OR (thu sach)) bai nghe du hoc ) OR ( thu ((hoach ha) OR (hoach va)) nghiem so hoc )).
• Adding a wildcard symbol may retrieve word variants: (( ((te sach) or (thu sach)) bai nghe du hoc ) or ( thu ((hoach ha) or (hoach va)) nghiem so hoc ))*.