Perhaps you should try some spelling variations:
thiet tach » chiet tach, thien hach, thuat tach
nhung cong » dung cong, thong cong, hang cong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
trinh cua » trinh luat, trinh quan, trinh luan
van thanh » ban thanh, van tuan
tinh cua » sinh cua, tinh chat, tranh cua
van toan » van tuan, van tan, manh toan

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