Perhaps you should try some spelling variations:
sach truc » cach thuc, sach tren, sach thu
va triet » va trien, ve triet, cua triet
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
lam xuc » cam xuc, lam duoc
va dinh » van dinh, va kinh, va tinh
dinh tu » danh tu, dinh cu, tinh tu
va lam » van lam, va lap
xuc va » duc va, tuc va, luc va
x hoi » xa hoi, o hoi, 5 hoi
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach truc nano ((x hoi) OR (x ho)). hieu va lam xuc va dinh tu ((va triet) or (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach truc nano ((x hoi) OR (x ho)). hieu va lam xuc va dinh tu ((va triet) OR (va thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach truc nano ((x hoi) OR (x ho)). hieu va lam xuc va dinh tu ((va triet) or (va thiet))".
• Adding a wildcard symbol may retrieve word variants: tu sach truc nano ((x hoi) OR (x ho)). hieu va lam xuc va dinh tu ((va triet) or (va thiet))*.