Perhaps you should try some spelling variations:
hien manh » hien hanh, tien manh, hieu manh
trinh vat » trinh van, trinh luat, sinh vat
nang cong » nang song, dang cong, hang cong
bang cong » dang cong, bang song, hang cong
trinh va » trinh van, trinh ve, trinh vi
tan phan » toan phan, than phan, van 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 hien manh - canh ((trinh va) OR (trinh vat)) ((nang cong) or (bang cong)) tan phan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien manh - canh ((trinh va) OR (trinh vat)) ((nang cong) OR (bang cong)) tan phan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien manh - canh ((trinh va) OR (trinh vat)) ((nang cong) or (bang cong)) tan phan cau".
• Adding a wildcard symbol may retrieve word variants: hoc hien manh - canh ((trinh va) OR (trinh vat)) ((nang cong) or (bang cong)) tan phan cau*.