Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
thuc dan » thuc hanh, hoc dan, thuc vat
su sach » so sach, vu sach
ky tang » ky nang, ky dang, kho tang
hieu ve » hieu va, hieu van
dan van » dang van, doan van, dao van
y tang » 6 tang, 7 tang, 5 tang
ve cac » va cac, vien cac
van da » van dao, van dau, van dan
da cua » dai cua, day cua, dan cua
cua te » cua tu

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 ((y tang) or (ky tang)) van hoa. hieu ve cac thuc dan van da cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y tang) OR (ky tang)) van hoa. hieu ve cac thuc dan van da cua te.
• Adding a wildcard symbol may retrieve word variants: su sach ((y tang) or (ky tang)) van hoa. hieu ve cac thuc dan van da cua te*.