Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
bai thuc » bai thuoc, bao thuc, dai thuc
vat hanh » vat thanh, van hanh, va hanh
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
vai cua » hai cua, lai cua, bai cua
y nang » ky nang, ly nang, v nang

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 xa hoi. hieu va bai thuc vat hanh ((vai cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y nang xa hoi. hieu va bai thuc vat hanh ((vai cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y nang xa hoi. hieu va bai thuc vat hanh ((vai cua) or (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y nang xa hoi. hieu va bai thuc vat hanh ((vai cua) or (dai cua)) tre*.