Perhaps you should try some spelling variations:
thi nghiem » thuc nghiem
thu nghiem » thuc nghiem
nghiem te » nghiem de, nghiem ve, nghiem tien
nghiem ad » nghiem d, nghiem ban, nghiem lam
khac thi » khau thi, khuc thi, khuat thi
vu khach » vu khanh, vu khac, vay khach
su khac » vu khac, se khac, bui khac

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( su khac thi nghiem te hoc ) OR ( ((vu bach) OR (vu khach)) thu nghiem ad hoc ))~.
• Adding a wildcard symbol may retrieve word variants: (( su khac thi nghiem te hoc ) or ( ((vu bach) or (vu khach)) thu nghiem ad hoc ))*.