Perhaps you should try some spelling variations:
nghiem su » nghiem xu, nghiem ngu, nghiem dau
hoach ha » hoach xay, hoach hoi, hoach su
hoach va » hoach xay, hanh va, doanh va
sach bai » sach dao, cac bai
sach xa » sach dao, sach nha
nghe di » nghe vi, nghe dien, nghe dan
su hoc » tu hoc, du hoc, so hoc
di hoc » dai hoc, dia hoc, li hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu ((sach bai) or (sach xa)) nghe di hoc ) or ( thu ((hoach ha) OR (hoach va)) nghiem su hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu ((sach bai) OR (sach xa)) nghe di hoc ) OR ( thu ((hoach ha) OR (hoach va)) nghiem su hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu ((sach bai) or (sach xa)) nghe di hoc ) or ( thu ((hoach ha) OR (hoach va)) nghiem su hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( tu ((sach bai) or (sach xa)) nghe di hoc ) or ( thu ((hoach ha) OR (hoach va)) nghiem su hoc ))*.