Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh vai » hanh vi, hanh va, hanh tai
cau tren » cu tren, dau tren, ca tren
su sach » so sach, vu sach
ky sang » ky dang, ky tang, duy sang
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
vai cau » va cau, van cau, vai cac
ve cac » va cac, vien cac

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 sang) or (ky nang)) mai hoi. hieu ve cac duc van hanh vai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky sang) OR (ky nang)) mai hoi. hieu ve cac duc van hanh vai cau tren.
• Adding a wildcard symbol may retrieve word variants: su sach ((ky sang) or (ky nang)) mai hoi. hieu ve cac duc van hanh vai cau tren*.