Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam tuc » nam thuc, nam truc, nam tu
tai cuu » tai cuc, tai buu, tai cua
va hanh » van hanh, va thanh, va danh
xa hanh » xa thanh, xa khanh, da hanh
cuu tre » cua tre, cau tren, cau treo
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
va nam » van nam, ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ky nang ma hoi. hieu va nam tuc ((xa hanh) OR (va hanh)) tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang ma hoi. hieu va nam tuc ((xa hanh) OR (va hanh)) tai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky nang ma hoi. hieu va nam tuc ((xa hanh) OR (va hanh)) tai cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky nang ma hoi. hieu va nam tuc ((xa hanh) OR (va hanh)) tai cuu tre*.