Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
nghiem thuoc » nghiem duoc, nghiem hoa, nghi thuc
sach trinh » hanh trinh, sach kinh, sach tren
sach tranh » canh tranh
nghien du » nghiep du, nghien cuu, nghiem dau
sach minh » sach kinh, sach danh, sac tinh
thuoc hoc » thuoc ho, thuoc nhom, thuong hoc
te sach » toc sach
du hoc » tu hoc, duoc hoc

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

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