Perhaps you should try some spelling variations:
tinh doi » trinh doc, trinh do, tinh hoc
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
cau tuc » cau truc, cau tu, cau phuc
cau luc » cau truc, cau phuc
doi cuu » doi cua, doi cuoc
cuu tre » cua tre, cau tren, cau treo
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

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

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