Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
khach trinh » kha trinh, thanh trinh
hanh trinh » canh tranh, hanh chinh
vu khach » vu khanh, vu khac, vay khach
nghien d » nghiem d, nghien o, nghiem de
co hanh » co thanh, co phanh, co anh
d hoc » du hoc, ad hoc, de hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( co hanh trinh nghien ((tu hoc) or (te hoc)) ) or ( vu khach trinh nghien d hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( co hanh trinh nghien ((tu hoc) OR (te hoc)) ) OR ( vu khach trinh nghien d hoc )).
• Adding a wildcard symbol may retrieve word variants: (( co hanh trinh nghien ((tu hoc) or (te hoc)) ) or ( vu khach trinh nghien d hoc ))*.