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

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

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