Perhaps you should try some spelling variations:
tuan doanh » toan doanh, nhuan doanh, tuan anh
doanh khoa » toan khoa
sanh khai » manh khai, minh khai, sinh khoi
sinh khoa » sinh hoc, sinh hoat, anh khoa
sach tri » sach tai, sach tren, sach truc
tri tuan » tri quan, tran tuan, tri tue
khoa hai » khoa hoi, khoa tai, khoa bai
khai hai » hai hai, khai thac, khai hoan
hai sinh » phai sinh, thai sinh, tai sinh
khoa han » khoa than, hoa han, khoa can
tu sach » thu sach, su sach, te sach
so sanh » do sanh
tong » cong, dong, song

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu sach tri tuan doanh khoa hai phong ) or ( so sanh khai hai sinh khoa han tong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach tri tuan doanh khoa hai phong ) OR ( so sanh khai hai sinh khoa han tong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach tri tuan doanh khoa hai phong ) or ( so sanh khai hai sinh khoa han tong ))*.