Perhaps you should try some spelling variations:
mach tinh » mach tich, manh tinh, trach tinh
tinh dau » tinh da, trinh dan, trinh dao
don gian » dan gian
hoc giao » hoc cao
tu mach » tu cach, tu manh, tu hach
tu hinh » tu minh, su hinh, tu kinh
tu hanh » du hanh, lu hanh, thuc hanh

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 dau - don gian ) or ( ((tu hinh) OR (tu hanh)) lich su - hoc giao ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu mach tinh dau - don gian ) OR ( ((tu hinh) OR (tu hanh)) lich su - hoc giao )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu mach tinh dau - don gian ) or ( ((tu hinh) OR (tu hanh)) lich su - hoc giao ))".
• Adding a wildcard symbol may retrieve word variants: (( tu mach tinh dau - don gian ) or ( ((tu hinh) OR (tu hanh)) lich su - hoc giao ))*.