Perhaps you should try some spelling variations:
thi nghiem » thuc nghiem
hoach thi » hoach thu, hoach toi, hoach thay
nghiem du » nghiem dau, nghiem d, nghiem de
su sach » so sach, vu sach
sach da » sach dao, sach dat, sach dau
da nghe » day nghe, va nghe, dang nghe
de hoc » te hoc, dien hoc
du hoc » tu hoc, duoc hoc
d hoc » ad hoc, y hoc, _ hoc

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( su sach da nghe ((d hoc) or (de hoc)) ) or ( thu hoach thi nghiem du hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach da nghe ((d hoc) OR (de hoc)) ) OR ( thu hoach thi nghiem du hoc )).
• Adding a wildcard symbol may retrieve word variants: (( su sach da nghe ((d hoc) or (de hoc)) ) or ( thu hoach thi nghiem du hoc ))*.