Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
cac duc » cac du, cao duc, cac dac
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
cua tre » cua te, cuu tre, cua triet
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 (tu sach)) ty nang xa hoi. lieu va cac duc ((va danh) OR (va hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ty nang xa hoi. lieu va cac duc ((va danh) OR (va hanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (tu sach)) ty nang xa hoi. lieu va cac duc ((va danh) OR (va hanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) ty nang xa hoi. lieu va cac duc ((va danh) OR (va hanh)) vi cua tre*.