Perhaps you should try some spelling variations:
doan thien » hoan thien, doan thi, toan thiet
thien anh » thien danh, tien anh, thien thanh
trinh van » trinh han, trinh quan, trinh toan
trinh va » trinh vat, trinh ve, trinh vi
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: doan thien anh - hanh ((trinh va) OR (trinh van)) nhung ((cong dan) or (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doan thien anh - hanh ((trinh va) OR (trinh van)) nhung ((cong dan) OR (cong san)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doan thien anh - hanh ((trinh va) OR (trinh van)) nhung ((cong dan) or (cong san)) toan cau".
• Adding a wildcard symbol may retrieve word variants: doan thien anh - hanh ((trinh va) OR (trinh van)) nhung ((cong dan) or (cong san)) toan cau*.