Perhaps you should try some spelling variations:
khuyen cao » nguyen cao, chuyen lao, huyen cho
cong luong » cong thuong, nang luong, cong cong
huyen cao » huyen bao, huyen cho, huyen dao
cach thuc » anh thuc, cac thu
ban ve » ban va
ky tai » ly tai, ky thi, kg tai
ve ky » va ky, ke ky
dong » dung

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((huyen cao) OR (khuyen cao)) cach thuc đe co ban ve ky tai ((cong luong) or (cong dong))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((huyen cao) OR (khuyen cao)) cach thuc đe co ban ve ky tai ((cong luong) OR (cong dong)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((huyen cao) OR (khuyen cao)) cach thuc đe co ban ve ky tai ((cong luong) or (cong dong))".
• Adding a wildcard symbol may retrieve word variants: ((huyen cao) OR (khuyen cao)) cach thuc đe co ban ve ky tai ((cong luong) or (cong dong))*.