Perhaps you should try some spelling variations:
tu sach » thu sach, te sach, tu cach
tinh di » tinh doi, trinh di, tinh da
va tinh » may tinh
truc va » thuc va, thuc vat, trung va
hieu ve » hieu va, hieu van
tu nang » tru nang, tu nong, tu nano
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (su sach)) tu nang x hoi. ((hieu ve) or (hieu qua)) cau truc va tinh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) tu nang x hoi. ((hieu ve) OR (hieu qua)) cau truc va tinh di cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) tu nang x hoi. ((hieu ve) or (hieu qua)) cau truc va tinh di cua tre*.