Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
ban hanh » ban hang
ban banh » ban anh, ban danh, ban thanh
tu sach » su sach, te sach, tu cach
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
va cam » va cham, va cac, va cao
nang o » nang co, nang ho, nang ro
di cuu » di cau, di cua, dinh cuu
o hai » co hai, so hai, o lai

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 (thu sach)) ky nang o hai. hieu va cam xuc ((ban banh) OR (ban hanh)) di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang o hai. hieu va cam xuc ((ban banh) OR (ban hanh)) di cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang o hai. hieu va cam xuc ((ban banh) OR (ban hanh)) di cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang o hai. hieu va cam xuc ((ban banh) OR (ban hanh)) di cuu tre*.