Perhaps you should try some spelling variations:
sac tinh » dac tinh, cac tinh, sat tinh
hoc giao » hoc cao
don gian » dan gian
su sach » vu sach
so sach » so sanh, bo sach, co sach
kinh su » kinh suu, hinh su, dinh su
tinh su » trinh su, hinh su, tinh tu
tu sac » tu sach, tu cac, tu san

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

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