Perhaps you should try some spelling variations:
dao nghien » dau nghien, vao nghien, cao nghien
nghien dau » nghiep dau, nghien cuu, nghiep cau
sach tranh » canh tranh
nghiem dau » nghiep dau, nghiem va, nghiem ban
khanh tra » thanh tra, khanh trach, khanh hoa
sach dao » lanh dao
te sach » toc sach
dau hoc » dai hoc, du hoc, dan 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 nghien dau hoc ) or ( thu ((khanh tra) or (sach tranh)) nghiem dau hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach dao nghien dau hoc ) OR ( thu ((khanh tra) OR (sach tranh)) nghiem dau hoc )).
• Adding a wildcard symbol may retrieve word variants: (( te sach dao nghien dau hoc ) or ( thu ((khanh tra) or (sach tranh)) nghiem dau hoc ))*.