Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
chieu sang » chieu sach, chieu xanh, hieu lang
hanh trinh » canh tranh, hanh chinh
nhung cong » dung cong, hang cong, nhung don
thong cong » trong cong, tong cong, thong thong
trinh vat » trinh van, trinh luat, sinh vat
van toan » van tuan, van tan, van thanh
toan tap » toan ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu khang) or (chieu sang)) - hanh trinh vat ((nhung cong) OR (thong cong)) van toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu khang) OR (chieu sang)) - hanh trinh vat ((nhung cong) OR (thong cong)) van toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu khang) or (chieu sang)) - hanh trinh vat ((nhung cong) OR (thong cong)) van toan tap".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu khang) or (chieu sang)) - hanh trinh vat ((nhung cong) OR (thong cong)) van toan tap*.