Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
chieu tinh » lieu tinh, chau tinh, kieu tinh
hanh tang » hanh trang, anh tang, hanh mang
cong tan » cong tac, cong san, cong thanh
tran ban » tranh ban, tran van, tran bai
toan ban » van ban
tang va » trang va, tang van, thang va

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: hoc ((chieu tinh) OR (trieu tinh)) - hanh tang va nhung cong tan ((tran ban) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu tinh) OR (trieu tinh)) - hanh tang va nhung cong tan ((tran ban) or (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu tinh) OR (trieu tinh)) - hanh tang va nhung cong tan ((tran ban) or (toan ban))*.