Perhaps you should try some spelling variations:
nghiep su » nghiep sua, nghiep vu, nghiep so
sach dao » lanh dao
dao nghe » day nghe, da nghe, dat nghe
dien hoc » dien hoa, khien hoc, tin hoc
hoach va » hoach xay, doanh va, hoa va
tu sach » thu sach, su sach, te sach
hanh va » hang va, hanh vi
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 dao nghe ((d hoc) or (dien hoc)) ) or ( thu ((hoach va) OR (hanh va)) nghiep su hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach dao nghe ((d hoc) OR (dien hoc)) ) OR ( thu ((hoach va) OR (hanh va)) nghiep su hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu sach dao nghe ((d hoc) or (dien hoc)) ) or ( thu ((hoach va) OR (hanh va)) nghiep su hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( tu sach dao nghe ((d hoc) or (dien hoc)) ) or ( thu ((hoach va) OR (hanh va)) nghiep su hoc ))*.