Perhaps you should try some spelling variations:
thiet tach » chiet tach, thien hach, thuat tach
truong cua » truong ca, truong quan, truong cao
nhung cong » dung cong, thong cong, hang cong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
trung cua » trung tuan, trung cap, dung cua
dan toan » van toan, dan than, manh toan
van tai » von tai, van tuan

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 tach - hanh ((trung cua) or (truong cua)) nhung cong ((dan toan) or (van tai)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet tach - hanh ((trung cua) OR (truong cua)) nhung cong ((dan toan) OR (van tai)) cao.
• Adding a wildcard symbol may retrieve word variants: hoc thiet tach - hanh ((trung cua) or (truong cua)) nhung cong ((dan toan) or (van tai)) cao*.