Perhaps you should try some spelling variations:
van hanh » van thanh, van anh, van ban
ban hanh » ban hang
ky sang » ky dang, ky tang, duy sang
dai hoi » dai hoc, dai hai, dai moi
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
vai cua » dai cua, hai cua, lai cua
tu sac » tu sach, tu cac, tu san
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ((ky sang) or (ky nang)) dai hoi. hieu vu cham soc ((van hanh) OR (ban hanh)) vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ((ky sang) OR (ky nang)) dai hoi. hieu vu cham soc ((van hanh) OR (ban hanh)) vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ((ky sang) or (ky nang)) dai hoi. hieu vu cham soc ((van hanh) OR (ban hanh)) vai cua te".
• Adding a wildcard symbol may retrieve word variants: tu sac ((ky sang) or (ky nang)) dai hoi. hieu vu cham soc ((van hanh) OR (ban hanh)) vai cua te*.