Perhaps you should try some spelling variations:
dan thanh » dang thanh, danh thanh, ban thanh
va trien » va truyen, va thiet, va tuyen
thuc dan » thuc hanh, hoc dan, thuc vat
va cham » va chat, va tham
sach ty » sach y, sach tu, sach thu
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
va chim » va chi, ve chim, va chinh
ang xa » mang xa, dang xay, hoang xa
san va » san van, ban va, dan va

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 ty ((ang xa) or (lang xa)) hoi. hieu ((va chim) or (va cham)) thuc dan thanh san va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((ang xa) OR (lang xa)) hoi. hieu ((va chim) OR (va cham)) thuc dan thanh san va trien.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((ang xa) or (lang xa)) hoi. hieu ((va chim) or (va cham)) thuc dan thanh san va trien*.