Perhaps you should try some spelling variations:
nhung phuong » dung phuong, nhu phuong, truong phuong
hanh truong » hanh trong, anh truong, manh truong
thiet tach » chiet tach, thien hach, thuat tach
truong ham » truong dai, truong cao, truong dao
nhung cong » dung cong, thong cong, hang cong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
dan toan » dan than, manh toan, xuan toan
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 tach - hanh truong ham ((nhung cong) or (nhung phuong)) ((dan toan) OR (van toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet tach - hanh truong ham ((nhung cong) OR (nhung phuong)) ((dan toan) OR (van toan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet tach - hanh truong ham ((nhung cong) or (nhung phuong)) ((dan toan) OR (van toan)) cao".
• Adding a wildcard symbol may retrieve word variants: hoc thiet tach - hanh truong ham ((nhung cong) or (nhung phuong)) ((dan toan) OR (van toan)) cao*.