Perhaps you should try some spelling variations:
thiet anh » thuyet anh, thien danh, thich anh
thien anh » thien danh, tien anh, thien thanh
trinh vat » trinh van, trinh luat, sinh vat
tong cong » trong cong, cong cong, dung cong
trinh va » trinh van, trinh ve, trinh vi
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than tap » toan tap, han tap, phan tap

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

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