Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh noi » ha noi, hanh vi, nang noi
hieu van » thien van, lieu va, hieu ve
hanh doi » thanh doi, hang doi, hanh moi
nam tuc » nam thuc, nam truc, nam tu
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
tuc va » thuc va, truc va, tuc xa
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y nang ma hoi. ((hieu van) or (hieu va)) nam tuc va ((hanh doi) or (hanh noi)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ma hoi. ((hieu van) OR (hieu va)) nam tuc va ((hanh doi) OR (hanh noi)) cuu tre.
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ma hoi. ((hieu van) or (hieu va)) nam tuc va ((hanh doi) or (hanh noi)) cuu tre*.