Perhaps you should try some spelling variations:
mach tinh » mach tich, manh tinh, trach tinh
toan giao » ton giao, toan cao
ban mach » ban sach, ranh mach, ban hanh
tinh son » tinh toan, dinh so, tinh hoc
bac ninh » xac dinh
don gian » dan gian
ninh su » hinh su, dinh su, tinh su
vu bac » vu bach, vu ban, xu bac

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( ban mach tinh son - ((toan giao) OR (hoa giao)) ) or ( vu bac ninh su - don gian ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ban mach tinh son - ((toan giao) OR (hoa giao)) ) OR ( vu bac ninh su - don gian )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ban mach tinh son - ((toan giao) OR (hoa giao)) ) or ( vu bac ninh su - don gian ))".
• Adding a wildcard symbol may retrieve word variants: (( ban mach tinh son - ((toan giao) OR (hoa giao)) ) or ( vu bac ninh su - don gian ))*.