Perhaps you should try some spelling variations:
phuong cong » phuong dong, phung cong, phuong hoang
thiet tach » chiet tach, thien hach, thuat tach
trinh quan » tinh quang, trinh luat, trinh han
phong cong » phong chong, thong cong, chong cong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
trinh cua » tinh cua, trinh luat, trinh luan
dan than » dan chan, ban than, van than
than ban » thanh ban, toan ban, than man

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 (trinh quan)) ((phuong cong) or (phong cong)) dan than ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet tach - hanh ((trinh cua) OR (trinh quan)) ((phuong cong) OR (phong cong)) dan than ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet tach - hanh ((trinh cua) OR (trinh quan)) ((phuong cong) or (phong cong)) dan than ban".
• Adding a wildcard symbol may retrieve word variants: hoc thiet tach - hanh ((trinh cua) OR (trinh quan)) ((phuong cong) or (phong cong)) dan than ban*.