Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
va thanh » gia thanh, ban thanh, va tinh
thanh vi » hanh vi, thanh va, thanh ve
sach ty » sach y, sach tu, xach tay
hieu ve » hieu va, hieu van
ve giao » te giao, viet giao, van giao
luu tre » luu tru, cuu tre, luy tre
vi luu » vi lua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sach ty) OR (sach thu)) nang ((x ho) or (xa hoi)). hieu ve giao duc va thanh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach ty) OR (sach thu)) nang ((x ho) OR (xa hoi)). hieu ve giao duc va thanh vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach ty) OR (sach thu)) nang ((x ho) or (xa hoi)). hieu ve giao duc va thanh vi luu tre".
• Adding a wildcard symbol may retrieve word variants: so ((sach ty) OR (sach thu)) nang ((x ho) or (xa hoi)). hieu ve giao duc va thanh vi luu tre*.