Perhaps you should try some spelling variations:
cam truc » cau truc, nam truc, lam truoc
so sach » so sanh, bo sach, co sach
nang ma » tang ma, sang ma, mang may
qua cam » qua cham, qua cac, qua ca
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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: so sach y ((nang ma) OR (nang cao)) hoi. hieu qua cam truc va hanh ((vi cua) OR (di cua)) triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y ((nang ma) OR (nang cao)) hoi. hieu qua cam truc va hanh ((vi cua) or (di cua)) triet~".
• Adding a wildcard symbol may retrieve word variants: so sach y ((nang ma) OR (nang cao)) hoi. hieu qua cam truc va hanh ((vi cua) or (di cua)) triet*.