Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
vu nang » vuc nang, va nang, vu dang
hieu ve » hieu van
hieu va » lieu va, hieu qua
y nang » ky nang, ly nang, v nang
vi cua » vai cua, di cua
cua tu » cua tuc, cua su, cua cu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y nang) OR (vu nang)) x ho. ((hieu ve) OR (hieu va)) nam thuc vat hanh vi cua tu~.
• Adding a wildcard symbol may retrieve word variants: su sach ((y nang) or (vu nang)) x ho. ((hieu ve) or (hieu va)) nam thuc vat hanh vi cua tu*.