Perhaps you should try some spelling variations:
cach viet » bach viet, anh viet, danh viet
nam thuc » nam thuoc, nam thu, nam tu
dan manh » dang manh, doan manh, van manh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
manh va » hanh va, anh va, minh va
va cach » va cac
x hoi » xa hoi, o hoi, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ((x hoi) OR (x ho)). hieu ve ((nam thuc) or (am thuc)) dan manh va cach viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((x hoi) OR (x ho)). hieu ve ((nam thuc) OR (am thuc)) dan manh va cach viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((x hoi) OR (x ho)). hieu ve ((nam thuc) or (am thuc)) dan manh va cach viet*".