Perhaps you should try some spelling variations:
khoan pho » khoan nhoi, khoan phai, khoan hoi
pho thong » he thong
hoc thong » hoc thuong, hoc trong, hoc hong
sanh tri » thanh tri, dinh tri, minh tri
sach dao » lanh dao
dac khoa » da khoa, dai khoa, dau khoa
khoa hoc » hoa hoc
so sanh » do sanh
tu sach » thu sach, su sach, te sach
tri le » thi le, tri lieu
le cac » ve cac, le cap, le cau
dao le » do le, dao ve, hao le
le dac » le dan, le duc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( so sanh tri le cac khoan pho thong ) or ( tu sach dao le dac khoa hoc thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sanh tri le cac khoan pho thong ) OR ( tu sach dao le dac khoa hoc thong )).
• Adding a wildcard symbol may retrieve word variants: (( so sanh tri le cac khoan pho thong ) or ( tu sach dao le dac khoa hoc thong ))*.