Perhaps you should try some spelling variations:
van xanh » van anh, van hanh, van manh
so sach » so sanh, bo sach, hoc sach
co sach » bo sach, cuon sach, hoc sach
xanh di » danh di, vanh dai, xanh tai
su tien » su kien, su hien, tu tieng
du van » duy van, duc van, tu van
di su » doi su, ki su, da su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (co sach)) ky nang x ho. lieu va cac du van xanh di su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (co sach)) ky nang x ho. lieu va cac du van xanh di su tien.
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (co sach)) ky nang x ho. lieu va cac du van xanh di su tien*.