Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
doc sach » hoc sach, toc sach, nuoc sach
vien cac » vien bach, vien dai, vien da
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
ve cac » va cac
luc va » duc va, tuc va, loc va
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (doc sach)) ky nang x ho. hieu ((ve cac) OR (vien cac)) luc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (doc sach)) ky nang x ho. hieu ((ve cac) OR (vien cac)) luc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (doc sach)) ky nang x ho. hieu ((ve cac) OR (vien cac)) luc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (doc sach)) ky nang x ho. hieu ((ve cac) OR (vien cac)) luc va hanh vi cua tre*.