Perhaps you should try some spelling variations:
sach tranh » canh tranh
nghiem de » nghiem d, nghiem do, nghiem ve
nghiem te » nghiem ve, nghiem tien, nghiem tren
nha nhiem » nha nghien, thai nhiem, nha hieu
nhiem ve » nghiem ve, nhiem va, nghiem va
su sach » so sach, vu sach
ve hoc » te hoc, va hoc, vi 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 tranh ((nghiem de) or (nghiem te)) hoc ) or ( su sach nha nhiem ve hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach tranh ((nghiem de) OR (nghiem te)) hoc ) OR ( su sach nha nhiem ve hoc )).
• Adding a wildcard symbol may retrieve word variants: (( su sach tranh ((nghiem de) or (nghiem te)) hoc ) or ( su sach nha nhiem ve hoc ))*.