Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
van hanh » van thanh, ban hanh, van anh
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
va danh » va dinh, va dan, va hanh
noi cuu » noi cua, nhim cuu
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
ve cac » va cac, vien cac

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)) y nang ma hoa. hieu ve cac nuoc ((va danh) or (van hanh)) noi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y nang ma hoa. hieu ve cac nuoc ((va danh) OR (van hanh)) noi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y nang ma hoa. hieu ve cac nuoc ((va danh) or (van hanh)) noi cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y nang ma hoa. hieu ve cac nuoc ((va danh) or (van hanh)) noi cuu tre*.