Perhaps you should try some spelling variations:
phuong dan » phuong danh, phuong doan, huong dan
hieu manh » chieu xanh, hieu nganh, dieu hanh
trung can » trung cap, trung van, trong can
hoc hieu » hoc thieu, hoc hien, doc hieu
tung can » tung dan, trung cap, tung manh
dan toan » van toan, dan than, manh toan
toan cau » toan cao, toan ban, toan tap

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 manh - thanh ((tung can) OR (trung can)) bang phuong dan toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu manh - thanh ((tung can) OR (trung can)) bang phuong dan toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc hieu manh - thanh ((tung can) OR (trung can)) bang phuong dan toan cau*.