Perhaps you should try some spelling variations:
thuong cong » thong cong, thuong con, thuong dong
khi xanh » khia canh, thi hanh, thi oanh
tung hoc » trung hoc, tuong hoc, dung hoc
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan tap » toan ban
thi anh » thi hanh, thi thanh, thich anh

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi ((khi xanh) OR (thi anh)) - thanh ((tung hoc) or (dung thuoc)) thuong cong tap toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((khi xanh) OR (thi anh)) - thanh ((tung hoc) OR (dung thuoc)) thuong cong tap toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi ((khi xanh) OR (thi anh)) - thanh ((tung hoc) or (dung thuoc)) thuong cong tap toan tap".
• Adding a wildcard symbol may retrieve word variants: doi ((khi xanh) OR (thi anh)) - thanh ((tung hoc) or (dung thuoc)) thuong cong tap toan tap*.