Perhaps you should try some spelling variations:
khoc tinh » khoa tinh, hoc tinh, kho tinh
hoc tich » hoc lich, hoc dich, hoc tach
hoc giao » hoc cao
tinh son » tinh toan, dinh so, tinh hoc
toan cao » toan ban, toan tap
ho tich » co tich, chu tich, thu tich
tu khoc » tu hoc, tu khoa, tu kho

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

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