Perhaps you should try some spelling variations:
nghiem su » nghiem xu, nghiem ngu, nghiem dau
ha nghiem » khao nghiem, thi nghiem, thu nghiem
sach day » sach dao, sach dat, sach hay
sach dau » sach dao, sach dat, sach mau
hoach ha » hoach va, hoach xay, hoach hoi
nghe d » nghe di, nghe _, nghe 新
su hoc » tu hoc, du hoc, so hoc
d hoc » du hoc, ad hoc, de 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 day) OR (sach dau)) nghe d hoc ) or ( thu hoach ha nghiem su hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu ((sach day) OR (sach dau)) nghe d hoc ) OR ( thu hoach ha nghiem su hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu ((sach day) OR (sach dau)) nghe d hoc ) or ( thu hoach ha nghiem su hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( tu ((sach day) OR (sach dau)) nghe d hoc ) or ( thu hoach ha nghiem su hoc ))*.