Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, trinh thiet, trinh dien
hanh trinh » canh tranh, hanh chinh
nghiem so » nghiem son, nghiep so, nghiem do
nghien y » nghiep y, nghiem y, nghien o
toc sach » hoc sach, doc sach, thuoc sach
tu hanh » du hanh, lu hanh, thuc hanh
so hoc » co hoc, mo hoc, so hoa
kinh » dinh, minh

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu hanh trinh nghien y hoc ) or ( toc sach kinh nghiem so hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu hanh trinh nghien y hoc ) OR ( toc sach kinh nghiem so hoc )).
• Adding a wildcard symbol may retrieve word variants: (( tu hanh trinh nghien y hoc ) or ( toc sach kinh nghiem so hoc ))*.