Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
va triet » va trien, ve triet, cua triet
nam thuc » nam thuoc, am thuc, nam thu
dinh tu » danh tu, dinh cu, tinh tu
va dinh » van dinh, va kinh, va tinh
thuc va » thuc vat, thuc dan, thuc day
su sach » vu sach
tu nano » truc nano
so sach » so sanh, bo sach, co sach
nano o » nano 1, nano cuo, nano mot
o hoi » co hoi, o hoc, o hai
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: ((su sach) or (so sach)) tu nano o hoi. hieu van nam thuc va dinh tu ((va triet) OR (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) tu nano o hoi. hieu van nam thuc va dinh tu ((va triet) OR (va thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) tu nano o hoi. hieu van nam thuc va dinh tu ((va triet) OR (va thiet))".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) tu nano o hoi. hieu van nam thuc va dinh tu ((va triet) OR (va thiet))*.