Perhaps you should try some spelling variations:
thu nghiem » thuc nghiem, thi nghiem
hoach thu » hoach thay, doanh thu, hoach su
nghiem su » nghiem xu, nghiem ngu, nghiem dau
dao nghe » day nghe, da nghe, nao nghe
dat nghe » day nghe, da nghe, dang nghe
te sach » toc sach
de hoc » te hoc, du hoc, dien hoc
su hoc » tu hoc, du hoc, so hoc
d hoc » du hoc, ad hoc, y hoc

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 ((dao nghe) OR (dat nghe)) ((d hoc) or (de hoc)) ) or ( thu hoach thu nghiem su hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach ((dao nghe) OR (dat nghe)) ((d hoc) OR (de hoc)) ) OR ( thu hoach thu nghiem su hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach ((dao nghe) OR (dat nghe)) ((d hoc) or (de hoc)) ) or ( thu hoach thu nghiem su hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( te sach ((dao nghe) OR (dat nghe)) ((d hoc) or (de hoc)) ) or ( thu hoach thu nghiem su hoc ))*.