Perhaps you should try some spelling variations:
cam truc » cau truc, lam truoc, nam truoc
nam truc » nam truoc, nam thuc, nam trung
so sach » so sanh, bo sach, co sach
va nang » van nang, da nang, cam nang
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
dan dai » can dai, dan dat, dan da
sach va » sach xa, sach ha, sach dao
thiet » thieu

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 va nang ma hoa. hieu ve ((cam truc) OR (nam truc)) va ((dan dai) OR (dat dai)) va thiet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach va nang ma hoa. hieu ve ((cam truc) or (nam truc)) va ((dan dai) OR (dat dai)) va thiet~".
• Adding a wildcard symbol may retrieve word variants: so sach va nang ma hoa. hieu ve ((cam truc) or (nam truc)) va ((dan dai) OR (dat dai)) va thiet*.