Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, nghiep nganh
canh trinh » canh tranh, hanh trinh, canh tinh
nhung cong » dung cong, thong cong, hang cong
hieu manh » chieu xanh, dieu hanh, hien hanh
nhanh cau » nhanh cay, thanh chau, nhanh ha
trinh va » trinh van, trinh vat, trinh ve
cong sat » cong suat, cong san, cong hat
nhan cau » phan cau, nhan sau, nhin cau

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