Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
dai cuu » dai cua, dai huu
dau dai » dat dai, sau dai, dau da
thuc va » thuc vat, thuc dan, thuc day
va chat » van chat, va phat, cao chat
tu nano » truc nano
tu nang » tru nang, tu nong, tu lang
cuu tre » cua tre, cau tren, cau treo
va dau » va dao
va co » vo co

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((tu nang) OR (tu nano)) xa hoi. hieu ((va chat) OR (va co)) thuc va dau dai cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((tu nang) OR (tu nano)) xa hoi. hieu ((va chat) or (va co)) thuc va dau dai cuu tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach ((tu nang) OR (tu nano)) xa hoi. hieu ((va chat) or (va co)) thuc va dau dai cuu tre*.