Perhaps you should try some spelling variations:
hanh trung » thanh trung, hanh trang, manh trung
trung cua » truong cua, trung tuan, trung cap
cua trong » cua truong, cua trung, qua trong
hieu luc » hieu luat
cong van » cong vang, cong san, song van
van han » van hanh, van phan, van nhan
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 trung cua trong cong van han tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu luc) OR (hieu qua)) - hanh trung cua trong cong van han tap.
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu luc) or (hieu qua)) - hanh trung cua trong cong van han tap*.