Perhaps you should try some spelling variations:
thuat mach » thuat sach, thuat tach, thuyet mach
than thong » than thuong, toan thong, tran thong
sinh nghe » sinh ngheo, tinh nghe, vinh nghe
pho thong » he thong
dao thuat » dao phat, va thuat, cac thuat
mach khoa » bach khoa, anh khoa, may khoa
khoa than » khoa luan, hoa thai, hoa tan
sanh tai » sang tai, hanh tai, anh tai
nghe pho » nghe cho, nghe phan, nghe khoa
so sanh » do sanh
tai hoc » thai hoc, dai hoc, bai hoc
tu lanh » tu hanh, tu lenh, tu manh

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 tai hoc sinh nghe pho thong ) or ( tu lanh dao thuat mach khoa than thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sanh tai hoc sinh nghe pho thong ) OR ( tu lanh dao thuat mach khoa than thong )).
• Adding a wildcard symbol may retrieve word variants: (( so sanh tai hoc sinh nghe pho thong ) or ( tu lanh dao thuat mach khoa than thong ))*.