Perhaps you should try some spelling variations:
khao nghiem » khao nghiep
hoach khao » hoach ha, hoach giao, hoach thay
nghiem su » nghiem xu, nghiem ngu, nghiem dau
bai nghe » thai nghe, van nghe, cap nghe
nam nghe » nang nghe, van nghe
tu sach » thu sach, su sach, te sach
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 ((bai nghe) or (nam nghe)) d hoc ) or ( thu hoach khao nghiem su hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach ((bai nghe) OR (nam nghe)) d hoc ) OR ( thu hoach khao nghiem su hoc )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach ((bai nghe) or (nam nghe)) d hoc ) or ( thu hoach khao nghiem su hoc ))*.