Perhaps you should try some spelling variations:
nang han » nang phan, nang hang, nang hanh
va thanh » gia thanh, ban thanh, va tinh
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va danh, ban hanh
tai cua » thai cua, tai cuc, tri cua
cau luc » cau truc, cau phuc
han hoi » phan hoi, dan hoi, van hoi
hieu va » lieu va, hieu qua
va cau » van cau, va cac, va dau
hai ky » thai ky, hai ly, sai ky

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

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