Perhaps you should try some spelling variations:
sach tao » sach dao, sach bao, sach tai
ban hanh » ban hang
cac quoc » cac nuoc, cac cuoc, cao quoc
cam quoc » cao quoc, nam quoc, han quoc
vu sach » vu bach, su sach, vu khach
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
hieu va » lieu va, hieu qua
co cau » bo cau
tao co » tao cao, tao con, tao cho

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 tao co cau hoi. hieu va ((cam quoc) or (cac quoc)) ban hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach tao co cau hoi. hieu va ((cam quoc) OR (cac quoc)) ban hanh vi ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: vu sach tao co cau hoi. hieu va ((cam quoc) or (cac quoc)) ban hanh vi ((cua tre) or (cuu tre))*.