Perhaps you should try some spelling variations:
kham duc » pham duc, kham cuoc, pham duy
tan hanh » tan thanh, tang hanh, toan hanh
dai hoi » dai hoc, dai hai, dai moi
hieu vu » hieu va, hieu ve, hieu su
vu kham » vu khanh
tu sai » tu bai, tu san, tu cai
sai ky » sac ky
ma hoi » mai hoi, xa hoi, ma hoa
di cua » doi cua, de cua, do cua

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 ((ma hoi) or (dai hoi)). hieu vu kham duc tan hanh ((di cua) OR (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sai ky nang ((ma hoi) OR (dai hoi)). hieu vu kham duc tan hanh ((di cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sai ky nang ((ma hoi) or (dai hoi)). hieu vu kham duc tan hanh ((di cua) OR (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sai ky nang ((ma hoi) or (dai hoi)). hieu vu kham duc tan hanh ((di cua) OR (dai cua)) tre*.