Perhaps you should try some spelling variations:
mach dinh » hoach dinh, xac dinh, mach dien
ton giao » toan giao, so giao, don gian
hoc giao » hoc cao
tu mach » tu cach, tu manh, tu hach
dinh du » dinh duc, dinh cu, dinh tu
tu tinh » tru tinh, thue tinh, thuy tinh
tu tin » thu tin, tu tieng, tru tinh

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 dinh du - ton giao ) or ( ((tu tinh) or (tu tin)) lich su - hoc giao ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu mach dinh du - ton giao ) OR ( ((tu tinh) OR (tu tin)) lich su - hoc giao )).
• Adding a wildcard symbol may retrieve word variants: (( tu mach dinh du - ton giao ) or ( ((tu tinh) or (tu tin)) lich su - hoc giao ))*.