Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
dang xay » dang van, van xay
danh vai » danh sai, danh va, doanh van
tu sach » thu sach, su sach, te sach
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, va hanh
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
lang ha » long ha
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 ((dang xay) or (lang ha)) hoi. hieu ((ve cac) OR (vien cac)) thuc va danh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((dang xay) OR (lang ha)) hoi. hieu ((ve cac) OR (vien cac)) thuc va danh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((dang xay) or (lang ha)) hoi. hieu ((ve cac) OR (vien cac)) thuc va danh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((dang xay) or (lang ha)) hoi. hieu ((ve cac) OR (vien cac)) thuc va danh vai cua tre*.