Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
tranh cua » doanh cua, manh cua
cua trong » cua truong, cua trung, qua trong
hieu luc » hieu luat
cong san » cong tac
tan tap » toan tap, tan tat, man tap
han tap » han tai, toan tap, nhan tai

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu luc) or (hieu qua)) - hanh tranh cua trong cong san ((tan tap) or (han tap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu luc) OR (hieu qua)) - hanh tranh cua trong cong san ((tan tap) OR (han tap)).
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu luc) or (hieu qua)) - hanh tranh cua trong cong san ((tan tap) or (han tap))*.