Perhaps you should try some spelling variations:
trinh vant » trinh han, trinh viet, trinh san
trinh van » trinh han, trinh quan, trinh toan
trinh vat » trinh luat, sinh vat, trinh han
dang cong » dung cong
cong manh » cong danh, duong manh, cong thanh
hoc dieu » hoc thieu, hoc hien
manh van » anh van, menh van, canh van

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc dieu hanh - hanh ((trinh van) OR (((trinh vant) OR (trinh vat)))) dang cong manh van ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc dieu hanh - hanh ((trinh van) or (((trinh vant) OR (trinh vat)))) dang cong manh van ban~".
• Adding a wildcard symbol may retrieve word variants: hoc dieu hanh - hanh ((trinh van) or (((trinh vant) OR (trinh vat)))) dang cong manh van ban*.