Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
nhung cong » dung cong, thong cong, hang cong
hieu manh » chieu xanh, hieu nganh, dieu hanh
hoc hieu » hoc thieu, hoc hien, doc hieu
trinh va » trinh van, trinh vat, trinh ve
phan cau » phan cac, phan tu, phan lap
phan dau » phan tu, hang dau

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 - canh trinh va ((nhung cong) or (trong cong)) vat ((phan cau) OR (phan dau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu manh - canh trinh va ((nhung cong) OR (trong cong)) vat ((phan cau) OR (phan dau)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu manh - canh trinh va ((nhung cong) or (trong cong)) vat ((phan cau) OR (phan dau))".
• Adding a wildcard symbol may retrieve word variants: hoc hieu manh - canh trinh va ((nhung cong) or (trong cong)) vat ((phan cau) OR (phan dau))*.