Perhaps you should try some spelling variations:
thuc dan » thuc hanh, hoc dan, thuc vat
cac thuc » cach thuc, cac thu, can thuc
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
tu hung » tu chung, tu nhung, tu vung
tu hang » thu hang, tu hanh, ty hang
dan va » dan ca, ban va, han va
ve cac » va cac, vien 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 ((tu hang) OR (tu hung)) xa hoi. hieu ve cac thuc dan ((dan va) or (doan va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((tu hang) OR (tu hung)) xa hoi. hieu ve cac thuc dan ((dan va) OR (doan va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((tu hang) OR (tu hung)) xa hoi. hieu ve cac thuc dan ((dan va) or (doan va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((tu hang) OR (tu hung)) xa hoi. hieu ve cac thuc dan ((dan va) or (doan va)) cua tre*.