Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, tu cach
te sach » toc sach
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
nam tu » nam thu, nam thuc
tu van » tu va
di cua » dai cua, doi cua, de 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) OR (te sach)) ky nang x ho. ((hieu quan) or (hieu qua)) nam tu van hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky nang x ho. ((hieu quan) OR (hieu qua)) nam tu van hanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (te sach)) ky nang x ho. ((hieu quan) or (hieu qua)) nam tu van hanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (te sach)) ky nang x ho. ((hieu quan) or (hieu qua)) nam tu van hanh di cua tre*.