Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
va hanh » va thanh, va danh, ban hanh
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet

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 ky nang xa hoi. ((lieu va) or (hieu qua)) pham duc ((va hanh) OR (van hanh)) doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang xa hoi. ((lieu va) OR (hieu qua)) pham duc ((va hanh) OR (van hanh)) doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang xa hoi. ((lieu va) or (hieu qua)) pham duc ((va hanh) OR (van hanh)) doi cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang xa hoi. ((lieu va) or (hieu qua)) pham duc ((va hanh) OR (van hanh)) doi cua tre*.