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, hang cong, nhung don
thong cong » trong cong, tong cong, thong thong
hieu manh » chieu xanh, dieu hanh, hien hanh
trinh va » trinh van, trinh vat, trinh ve
sat phan » sat nhan, vat phan, xuat phan
phan cau » phan dau, phan cac, phan tu

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) OR (thong cong)) sat phan 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) OR (thong cong)) sat phan 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) OR (thong cong)) sat phan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu manh) or (hieu nganh)) - canh trinh va ((nhung cong) OR (thong cong)) sat phan cau*.