Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
nang ra » nang ma, lang ra, nang ro
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
cuc tre » duc tre, cua tre, cuu tre
tu bac » tu ban, tu cac, tu bat
tu san » thu san, tu ban, tu can
ra lai » ra glai, ru lai, va lai
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: ((tu bac) or (tu san)) ky nang ra lai. hieu ve cac duc van hanh tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu bac) OR (tu san)) ky nang ra lai. hieu ve cac duc van hanh tai cuc tre.
• Adding a wildcard symbol may retrieve word variants: ((tu bac) or (tu san)) ky nang ra lai. hieu ve cac duc van hanh tai cuc tre*.