Perhaps you should try some spelling variations:
tru nang » tra nang, tri nang, truc nano
nam thuc » nam thuoc, am thuc, nam thu
vat hanh » vat thanh, van hanh, va hanh
su sach » so sach, vu sach
tu nang » tu nong, tu nano, tu lang
hieu ve » hieu va, hieu van
ve nam » he nam, va nam, le nam
vi cua » vai cua, di cua
de cua » le cua, te cua, dieu cua
x hoi » xa hoi, o hoi, x ho

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 ((tu nang) OR (tru nang)) x hoi. hieu ve nam thuc vat hanh ((vi cua) OR (de cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((tu nang) OR (tru nang)) x hoi. hieu ve nam thuc vat hanh ((vi cua) or (de cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ((tu nang) OR (tru nang)) x hoi. hieu ve nam thuc vat hanh ((vi cua) or (de cua)) tre*.