Perhaps you should try some spelling variations:
tan hanh » tan thanh, tang hanh, toan hanh
pham duy » pham duc
vu pham » su pham, vi pham, vu kham
vai cua » dai cua, hai cua, lai cua
duy tan » duy tuan, duc tan, duy van
hieu vu » hieu va, hieu ve, hieu su
mai hoi » mai khoi, lai hoi, mai doi
dai hoi » dai hoc, dai hai, dai moi
sai ky » sac ky
vi cua » di cua
tu sai » tu bai, tu san, tu cai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sai ky nang ((mai hoi) or (dai hoi)). hieu vu pham duy tan hanh ((vi cua) or (vai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sai ky nang ((mai hoi) OR (dai hoi)). hieu vu pham duy tan hanh ((vi cua) OR (vai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sai ky nang ((mai hoi) or (dai hoi)). hieu vu pham duy tan hanh ((vi cua) or (vai cua)) tre*.