Perhaps you should try some spelling variations:
thiet hach » thien hach, thuyet hach, thiet hai
thanh tung » thanh cong
nhung cong » dung cong, thong cong, hang cong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
dai nhung » ai nhung, dai khung, dap nhung
tung dai » trung dai, tuong dai, tung dan
van toan » van tuan, van tan, van thanh

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 tung dai nhung cong ((tan tran) or (van toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet hach - thanh tung dai nhung cong ((tan tran) OR (van toan)) cao.
• Adding a wildcard symbol may retrieve word variants: hoc thiet hach - thanh tung dai nhung cong ((tan tran) or (van toan)) cao*.