Perhaps you should try some spelling variations:
sach bao » sach dao, sach bai, sach bac
bao nano » tao nano, bao cao, cao nang
nano cau » nang cau, bang cau, nano va
qua pham » quan pham, quy pham, qua cham
dau tren » dau tien, dat tren, dau tieng
vu sach » vu bach, su sach, vu khach
duc van » duc va, duc tan, duc manh
van anh » van thanh, tuan anh, van minh
cua tre » cua te, cuu tre, cua triet
anh va » hanh va

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 bao nano cau hoi. hieu qua pham duc van anh va ((cua tre) or (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach bao nano cau hoi. hieu qua pham duc van anh va ((cua tre) OR (dau tren)).
• Adding a wildcard symbol may retrieve word variants: vu sach bao nano cau hoi. hieu qua pham duc van anh va ((cua tre) or (dau tren))*.