Perhaps you should try some spelling variations:
trinh quang » tinh quang, trinh quan, tranh quang
thiet hach » thien hach, thuyet hach, thiet hai
nhung cong » dung cong, thong cong, hang cong
trinh qua » trinh quan, trinh cua, trinh luat
ho thiet » hoc thiet, hoa thiet, so thiet
dung van » duong van, dung va, dang van

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ho thiet hach - hanh ((trinh qua) OR (trinh quang)) ((nhung cong) or (thong thong)) dung van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho thiet hach - hanh ((trinh qua) OR (trinh quang)) ((nhung cong) OR (thong thong)) dung van ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho thiet hach - hanh ((trinh qua) OR (trinh quang)) ((nhung cong) or (thong thong)) dung van ban".
• Adding a wildcard symbol may retrieve word variants: ho thiet hach - hanh ((trinh qua) OR (trinh quang)) ((nhung cong) or (thong thong)) dung van ban*.