Perhaps you should try some spelling variations:
thien van » thi van
thu sach » tu sach, thuat sach, thuoc sach
ban hang » ngan hang
va nang » van nang, cam nang, kha nang
da nang » cam nang, kha nang, cao nang
hang di » hang doi, hang vi, hang dien
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
di cua » dai cua, doi cua, de cua
o hoi » co hoi, o hoc, o hai

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 ((y nang) or (((va nang) OR (da nang)))) o hoi. thien van nam cua ban hang di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((y nang) OR (((va nang) OR (da nang)))) o hoi. thien van nam cua ban hang di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((y nang) or (((va nang) OR (da nang)))) o hoi. thien van nam cua ban hang di cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ((y nang) or (((va nang) OR (da nang)))) o hoi. thien van nam cua ban hang di cua tre*.