Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
kho tang » cao tang
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
ky tang » ky nang, ky dang, ky trong
dan vi » doan vi, don vi, dan va
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((ky tang) OR (kho tang)) van hoa. hieu van pham duc va ((dan vi) or (ban va)) cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ky tang) OR (kho tang)) van hoa. hieu van pham duc va ((dan vi) OR (ban va)) cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ky tang) OR (kho tang)) van hoa. hieu van pham duc va ((dan vi) or (ban va)) cua tu".
• Adding a wildcard symbol may retrieve word variants: thu sach ((ky tang) OR (kho tang)) van hoa. hieu van pham duc va ((dan vi) or (ban va)) cua tu*.