Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
va hanh » van hanh, va thanh, va danh
ve cac » va cac, vien cac
ve cau » ke cau, va cau, le cau
di cau » da cau, diem cau
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: tu sach ky nang ((x hoi) or (x ho)). hieu ve cac duc va hanh ((ve cau) or (di cau)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((x hoi) OR (x ho)). hieu ve cac duc va hanh ((ve cau) OR (di cau)) treo.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((x hoi) or (x ho)). hieu ve cac duc va hanh ((ve cau) or (di cau)) treo*.