Perhaps you should try some spelling variations:
trinh dan » trinh han, trinh san, trinh da
su triet » su viet, su tien, ve triet
thu sach » thuat sach, thuoc sach, thu hoach
tu quynh » thu quynh, thuy quynh, truc quynh
hieu ve » hieu va, hieu van
tu sach » su sach, te sach, tu cach
ty nang » ky nang, ty xang, ty hang
nang o » nang co, nang ho, nang ro
tu quy » tu duy
dan su » dang su
ve nam » he nam, va nam, le nam
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) OR (thu sach)) ty nang o hoi. hieu ve nam ((tu quy) or (tu quynh)) trinh dan su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty nang o hoi. hieu ve nam ((tu quy) OR (tu quynh)) trinh dan su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ty nang o hoi. hieu ve nam ((tu quy) or (tu quynh)) trinh dan su triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ty nang o hoi. hieu ve nam ((tu quy) or (tu quynh)) trinh dan su triet*.