Perhaps you should try some spelling variations:
khach trai » khac trai, khanh tra
thu nghiem » thuc nghiem, thi nghiem
kham trai » khac trai, pham tai, phai trai
nghiem mo » nghiem mon, nghiem moi, nghiem ma
sach thu » sach thue, sach thieu, sach tham
nghiem d » nghiem de, nghiem do, nghiem _
so sach » so sanh, bo sach, co sach
mo hoc » mon hoc, co 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: (( so sach thu nghiem d hoc ) or ( tu ((khach trai) or (kham trai)) nghiem mo hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sach thu nghiem d hoc ) OR ( tu ((khach trai) OR (kham trai)) nghiem mo hoc )).
• Adding a wildcard symbol may retrieve word variants: (( so sach thu nghiem d hoc ) or ( tu ((khach trai) or (kham trai)) nghiem mo hoc ))*.