Perhaps you should try some spelling variations:
khanh dinh » khanh linh, khanh vinh, hanh dinh
dinh cua » dinh cuu, sinh cua, dinh cu
vu khanh » vu thanh, van khanh, duy khanh
cua tre » cua te, cuu tre, cua triet
cao hoc » co hoc, cho hoc, chat hoc
ky lang » ky dang, ky tang, tay lang
hieu ve » hieu va, hieu van
tu ban » thu ban, te ban
am hoc » ad 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 ban ((ky lang) OR (ky nang)) xa hoi. hieu ve ((am hoc) or (cao hoc)) vu khanh dinh cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ban ((ky lang) OR (ky nang)) xa hoi. hieu ve ((am hoc) OR (cao hoc)) vu khanh dinh cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ban ((ky lang) OR (ky nang)) xa hoi. hieu ve ((am hoc) or (cao hoc)) vu khanh dinh cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ban ((ky lang) OR (ky nang)) xa hoi. hieu ve ((am hoc) or (cao hoc)) vu khanh dinh cua tre*.