Perhaps you should try some spelling variations:
nghiem su » nghiem xu, nghiem ngu, nghiem dau
ha nghiem » khao nghiem, thi nghiem, thu nghiem
hoach ha » hoach va, hoach xay, hoach hoi
te sach » toc sach
sach da » sach dao, sach dat, sach dau
da nghe » day nghe, va nghe, dang nghe
du hoc » tu hoc, duoc hoc
su hoc » tu hoc, so hoc, su ho

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