Perhaps you should try some spelling variations:
hoach hoi » hoc hoi, sach hoi
dang nghe » lang nghe, nang nghe, cong nghe
sach dang » sach dung, sach danh, sach nang
hoach ha » hoach va, hoach xay, hoach su
tu sach » thu sach, su sach, te sach
nghe de » nghe det, nghe di, nghe te
su hoa » su hoan, su hoat, su khoa
tu hoc » te hoc
de hoc » te hoc, du hoc, dien 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 dang nghe de hoc ) or ( thu ((hoach ha) OR (hoach hoi)) nghiem ((su hoa) or (tu hoc)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach dang nghe de hoc ) OR ( thu ((hoach ha) OR (hoach hoi)) nghiem ((su hoa) OR (tu hoc)) )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu sach dang nghe de hoc ) or ( thu ((hoach ha) OR (hoach hoi)) nghiem ((su hoa) or (tu hoc)) ))".
• Adding a wildcard symbol may retrieve word variants: (( tu sach dang nghe de hoc ) or ( thu ((hoach ha) OR (hoach hoi)) nghiem ((su hoa) or (tu hoc)) ))*.