Perhaps you should try some spelling variations:
nang han » nang phan, nang hang, nang hanh
thai cua » than cua, tri cua, dai cua
cau luc » cau truc, cau phuc
va hanh » van hanh, va thanh, va danh
hieu va » lieu va
han hoi » phan hoi, dan hoi, van hoi
sai ky » sac ky
luc va » duc va, tuc va, loc va
su sai » su tai, su hai, su dai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sai ky nang han hoi. ((hieu va) OR (hieu qua)) cau luc va hanh ((tai cuc) or (thai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sai ky nang han hoi. ((hieu va) OR (hieu qua)) cau luc va hanh ((tai cuc) OR (thai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sai ky nang han hoi. ((hieu va) OR (hieu qua)) cau luc va hanh ((tai cuc) or (thai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: su sai ky nang han hoi. ((hieu va) OR (hieu qua)) cau luc va hanh ((tai cuc) or (thai cua)) tre*.