Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
ban hanh » ban hang
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cua triet, dua tren
hanh de » hanh ve, hanh kem
duc ban » duc tan, duc van, dua ban
cam duc » cam xuc, cao duc, pham duc
van cam » van nam, van lam, van cau
cuu tre » cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((tu nano) or (truc nano)) xa hoi. hieu van cam duc ban hanh de ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((tu nano) OR (truc nano)) xa hoi. hieu van cam duc ban hanh de ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((tu nano) or (truc nano)) xa hoi. hieu van cam duc ban hanh de ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: thu sach ((tu nano) or (truc nano)) xa hoi. hieu van cam duc ban hanh de ((cua tre) OR (cuu tre))*.