Perhaps you should try some spelling variations:
nghiem su » nghiem xu, nghiem ngu, nghiem dau
ha nghiem » khao nghiem, thi nghiem, thu nghiem
dao nghe » day nghe, da nghe, dat nghe
hoach ha » hoach va, hoach xay, hoach hoi
nghe de » nghe det, nghe di, nghe te
tu sach » thu sach, te sach, vu sach
su sach » so sach, vu sach
tu cach » tu cac
de hoc » te hoc, du hoc, dien hoc
su hoc » tu hoc, du hoc, so 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) OR (tu cach))) or (su sach)) dao nghe de hoc ) or ( thu hoach ha nghiem su hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((((tu sach) OR (tu cach))) OR (su sach)) dao nghe de hoc ) OR ( thu hoach ha nghiem su hoc ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ((((tu sach) OR (tu cach))) or (su sach)) dao nghe de hoc ) or ( thu hoach ha nghiem su hoc ))*".