Perhaps you should try some spelling variations:
thai nghien » thai nguyen, thi nghiem, phap nghien
thai thai » thi thai, thai tai, thai thanh
nghien du » nghiep du, nghien cuu, nghiem dau
khac thi » khuc thi, khuat thi, khac trai
khau thi » khau tai, hau thi, khuat thi
nghiem d » nghiem de, nghiem do, nghiem _
ca thai » chat thai, hoa thai
du hoc » tu hoc, duoc hoc
d hoc » ad hoc, de hoc, y hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu ((khac thi) OR (khau thi)) nghiem d hoc ) or ( ca thai thai nghien du hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu ((khac thi) OR (khau thi)) nghiem d hoc ) OR ( ca thai thai nghien du hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu ((khac thi) OR (khau thi)) nghiem d hoc ) or ( ca thai thai nghien du hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( tu ((khac thi) OR (khau thi)) nghiem d hoc ) or ( ca thai thai nghien du hoc ))*.