Perhaps you should try some spelling variations:
dung gian » duong gian, dung giao, dung giam
hieu suat » hieu luat, hieu qua
gian dan » gian lang
dan tinh » doan tinh, dang tinh, dan trinh
tinh han » trinh han, tinh than, tinh hai
binh dan » minh danh, binh dinh, binh luan
van hieu » cao hieu
dan dat » dung dat, dong dat, dinh dat
dat van » dao van, dat va, dam van

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tin dung gian dan tinh han ) or ( binh dan dat van hieu suat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin dung gian dan tinh han ) OR ( binh dan dat van hieu suat ))*.