Perhaps you should try some spelling variations:
manh khai » minh khai, manh hai, dang khai
nam thuc » nam thuoc, nam thu, nam tu
san viet » gian viet, anh viet
dan manh » dang manh, doan manh, van manh
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
ty nang » ky nang, ty xang, ty hang
co viet » so viet, o viet, hoc viet
nang o » nang co, nang ho, nang ro
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 ty nang o hoi. hieu ve ((nam thuc) or (am thuc)) dan manh khai ((san viet) or (co viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang o hoi. hieu ve ((nam thuc) OR (am thuc)) dan manh khai ((san viet) OR (co viet)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang o hoi. hieu ve ((nam thuc) or (am thuc)) dan manh khai ((san viet) or (co viet))*.