Perhaps you should try some spelling variations:
sach tham » sach nha
tham nano » nham nang, tao nano, tham canh
nano cau » nang cau, bang cau, nano va
nam duoc » nam thuoc, da duoc, dat duoc
van hanh » van thanh, ban hanh, van anh
vu sach » vu bach, su sach, vu khach
cua tre » cua te, cua triet, dua tren
hanh va » hang va, hanh vi
cao duc » dao duc, cao suc, giao duc
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: vu sach tham nano cau hoi. hieu qua ((nam duoc) or (cao duc)) van hanh va ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach tham nano cau hoi. hieu qua ((nam duoc) OR (cao duc)) van hanh va ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: vu sach tham nano cau hoi. hieu qua ((nam duoc) or (cao duc)) van hanh va ((cua tre) or (cuu tre))*.