Perhaps you should try some spelling variations:
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
cam luc » cam xuc, cau luc
hieu va » lieu va, hieu qua
tu sach » thu sach, su sach, te sach
ky sang » ky dang, ky tang, duy sang
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, ma hoa, me hoi
va cam » va cham, va cac, va cao
luc va » duc va, tuc va, loc va
va cua » va chua, via cua, ca 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 sach ((ky sang) or (ky nang)) ((ma hoi) or (xa hoi)). hieu va cam luc va hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky sang) OR (ky nang)) ((ma hoi) OR (xa hoi)). hieu va cam luc va hanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky sang) or (ky nang)) ((ma hoi) or (xa hoi)). hieu va cam luc va hanh va cua tre*.