Perhaps you should try some spelling variations:
hoc thieu » hoc hien
trinh vat » trinh luat, sinh vat, trinh han
trinh van » trinh han, trinh quan, trinh toan
hang cong » dang cong, hang nong, bang cong
cong san » cong tac
san phan » san pham, van phan, sat phan
phan dau » phan tu, hang dau

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 thieu) OR (toc thieu)) xanh - canh ((trinh vat) OR (trinh van)) hang cong san phan dau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc thieu) OR (toc thieu)) xanh - canh ((trinh vat) or (trinh van)) hang cong san phan dau~".
• Adding a wildcard symbol may retrieve word variants: ((hoc thieu) OR (toc thieu)) xanh - canh ((trinh vat) or (trinh van)) hang cong san phan dau*.