Perhaps you should try some spelling variations:
trinh thuat » trinh luat, trinh thiet, trinh thuc
thieu tach » thien hach, chiet tach, chieu sach
hang huong » hang thuong, hang luong, hoang phuong
hoc thieu » toc thieu, hoc hien
trinh thi » trinh tai, dinh thi, trinh tu
dan toan » van toan, manh toan, xuan toan
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 thieu tach - hanh ((trinh thuat) or (trinh thi)) hang huong ((dan toan) OR (dan than)) tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu tach - hanh ((trinh thuat) OR (trinh thi)) hang huong ((dan toan) OR (dan than)) tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu tach - hanh ((trinh thuat) or (trinh thi)) hang huong ((dan toan) OR (dan than)) tap".
• Adding a wildcard symbol may retrieve word variants: hoc thieu tach - hanh ((trinh thuat) or (trinh thi)) hang huong ((dan toan) OR (dan than)) tap*.