Perhaps you should try some spelling variations:
vanh tai » van tai, hanh tai, anh tai
vanh dai » van dai, lanh dao, van dao
thuc dan » thuc hanh, hoc dan, thuc vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
va tham » van tham, va cham, va thanh
va nham » va cham, va nha, va kham
dang ha » dong ha, dung ha, lang ha
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet
ha hoi » hoa hoi, ha noi, xa hoi

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 ky dang ha hoi. hieu ((va nham) OR (va tham)) thuc dan ((vanh dai) or (vanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ha hoi. hieu ((va nham) OR (va tham)) thuc dan ((vanh dai) OR (vanh tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ha hoi. hieu ((va nham) OR (va tham)) thuc dan ((vanh dai) or (vanh tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ha hoi. hieu ((va nham) OR (va tham)) thuc dan ((vanh dai) or (vanh tai)) cua tre*.