Perhaps you should try some spelling variations:
thanh trung » thanh tung
thiet hach » thien hach, thuyet hach, thiet hai
cong huong » cong thuong, cong luong, cong hung
hoc thiet » hoc thieu, hoc thuyet, hoc hien
trung cua » truong cua, trung tuan, trung cap
dan than » dan chan, ban than, van than

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thiet hach - thanh trung cua cong huong ((dan than) or (dan ca)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet hach - thanh trung cua cong huong ((dan than) OR (dan ca)) cau.
• Adding a wildcard symbol may retrieve word variants: hoc thiet hach - thanh trung cua cong huong ((dan than) or (dan ca)) cau*.