Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
cua tre » cua te, cuu tre, cua triet
tai cua » thai cua, tai cuc, tri cua
va hanh » va thanh, va danh, ban hanh
cam luc » cam xuc, cau luc
hieu va » lieu va, hieu qua
hoa hoi » khoa hoi, hoa hoc, hoa doi
ky lang » ky nang, ky dang, ky tang
bai ky » ban ky, sai ky, bac ky
va cam » va cham, va cac, va cao
ha hoi » ha noi, xa hoi, va hoi
te bai » te bao, te tai, te ban

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

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