Perhaps you should try some spelling variations:
mach tinh » mach tich, manh tinh, trach tinh
ton giao » toan giao, so giao, don gian
hoc tich » hoc lich, ho tich, hoc dich
hoc giao » hoc cao
tu mach » tu cach, tu manh, tu hach
tinh su » trinh su, hinh su, tinh tu
tich so » tich bao, tinh son
tu hoc » te hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu mach tinh su - ton giao ) or ( tu hoc tich so - hoc giao ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu mach tinh su - ton giao ) OR ( tu hoc tich so - hoc giao )).
• Adding a wildcard symbol may retrieve word variants: (( tu mach tinh su - ton giao ) or ( tu hoc tich so - hoc giao ))*.