Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
manh vai » manh hai, manh va, manh khai
thuc dan » thuc hanh, thuc vat
vai cua » dai cua, hai cua, lai cua
tu sach » thu sach, te sach, tu cach
hieu ve » hieu va, hieu van
su sach » so sach, vu sach
nang o » nang co, nang ho, nang ro
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 (su sach)) ky nang o hoi. hieu ve nam ((thuc dan) OR (hoc dan)) manh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang o hoi. hieu ve nam ((thuc dan) OR (hoc dan)) manh vai cua viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ky nang o hoi. hieu ve nam ((thuc dan) OR (hoc dan)) manh vai cua viet*".