Perhaps you should try some spelling variations:
bac thanh » ban thanh, cac thanh, tai thanh
thuat hoa » thuat toan, thuyet hoa, thuat do
thanh ky » hanh ky, than ky, thanh tay
sach han » sach tham, sach danh, sach nang
su sach » so sach, vu sach
tu bac » tu ban, tu cac, tu bat
han ky » hanh ky, than ky, nhan ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu bac thanh ky thuat hoa hoc ) or ( su sach han ky thuat hoa hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu bac thanh ky thuat hoa hoc ) OR ( su sach han ky thuat hoa hoc )).
• Adding a wildcard symbol may retrieve word variants: (( tu bac thanh ky thuat hoa hoc ) or ( su sach han ky thuat hoa hoc ))*.