Perhaps you should try some spelling variations:
thiet hach » thien hach, thuyet hach, thiet hai
lanh tranh » canh tranh, lan tranh, hanh trinh
hoc thiet » hoc thieu, hoc thuyet, hoc hien
cua thong » cua thuong, cua khong, cua tong
tuong van » truong van, trong van, thong van
duong van » duong va, luong va, dang van
quan ban » quang ban, qua ban, quan van

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 hach - ((lanh tranh) or (hoang minh)) cua thong ((tuong van) OR (duong van)) quan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet hach - ((lanh tranh) OR (hoang minh)) cua thong ((tuong van) OR (duong van)) quan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet hach - ((lanh tranh) or (hoang minh)) cua thong ((tuong van) OR (duong van)) quan ban".
• Adding a wildcard symbol may retrieve word variants: hoc thiet hach - ((lanh tranh) or (hoang minh)) cua thong ((tuong van) OR (duong van)) quan ban*.