Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
cac thuc » cach thuc, cac thu, can thuc
vai cuu » vai cua
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
cuu tre » cua tre, cau tren, cau treo
hieu va » lieu va, hieu qua
nang xa » lang xa, nang ma, mang xa

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