Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
va hanh » va thanh, va danh, ban hanh
cua tre » cua te, cuu tre, cua triet
ve cau » ke cau, va cau, le cau
ve cac » va cac, vien cac
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: tu sach ky nang xa hoi. hieu ((ve cau) OR (ve cac)) luc ((va hanh) or (van hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu ((ve cau) OR (ve cac)) luc ((va hanh) OR (van hanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. hieu ((ve cau) OR (ve cac)) luc ((va hanh) or (van hanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu ((ve cau) OR (ve cac)) luc ((va hanh) or (van hanh)) vi cua tre*.