Perhaps you should try some spelling variations:
truong quan » trong quan, thong quan, luong quan
thiet hach » thien hach, thuyet hach, thiet hai
hoc thiet » hoc thieu, hoc thuyet, hoc hien
trung cua » truong cua, trung tuan, trung cap
nong cong » cong cong, tong cong, nang cong
san hanh » san thanh, ban hanh, dan hanh
van hanh » van thanh, ban hanh, van anh

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 thiet hach - thanh ((trung cua) OR (truong quan)) nong cong ((san hanh) OR (van hanh)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet hach - thanh ((trung cua) or (truong quan)) nong cong ((san hanh) OR (van hanh)) cau~".
• Adding a wildcard symbol may retrieve word variants: hoc thiet hach - thanh ((trung cua) or (truong quan)) nong cong ((san hanh) OR (van hanh)) cau*.