Perhaps you should try some spelling variations:
sach hoi » sach doi, sach moi, cach thoi
hieu van » hieu va, thien van, lieu va
sang tao » hang tai
doan vi » doan va, don vi, doan thi
va doan » va doanh, van doan, va dan
cam luc » cam xuc, cau luc
van cam » van nam, van lam, van cau
sach lo » sach dao, sach doi, sach moi
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va
vi cua » vai cua, di cua

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 lo) OR (sach hoi)) ((lang xa) or (sang tao)) hoi. hieu van cam luc va doan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sach lo) OR (sach hoi)) ((lang xa) OR (sang tao)) hoi. hieu van cam luc va doan vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu ((sach lo) OR (sach hoi)) ((lang xa) or (sang tao)) hoi. hieu van cam luc va doan vi cua tre".
• Adding a wildcard symbol may retrieve word variants: vu ((sach lo) OR (sach hoi)) ((lang xa) or (sang tao)) hoi. hieu van cam luc va doan vi cua tre*.