Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
hieu quag » hieu quang, hieu quan, thieu quang
tranh han » tranh hang, trinh han, tranh ban
han thong » han thuong, hang thong, nhan thong
cong tan » cong tac, cong san, cong thanh
tan khan » tan khang, tan nhan, toan khoan
khan cap » khan ap, than cap, khoan cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: thien ((hieu quag) or (hieu qua)) - canh tranh han thong cong tan khan cap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thien ((hieu quag) OR (hieu qua)) - canh tranh han thong cong tan khan cap.
• Adding a wildcard symbol may retrieve word variants: thien ((hieu quag) or (hieu qua)) - canh tranh han thong cong tan khan cap*.