Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
te sach » toc sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
ve tham » va tham, ve cham, vi tham
thuc va » thuc vat, thuc dan, thuc day
su tien » su kien, su hien, tu tieng
va dao » ca dao
dao vi » dao voi, dao ve, dao va
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky ((nang xa) OR (lang xa)) hoi. hieu ve tham thuc va dao vi su tien~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky ((nang xa) OR (lang xa)) hoi. hieu ve tham thuc va dao vi su tien".
• Adding a wildcard symbol may retrieve word variants: te sach ky ((nang xa) OR (lang xa)) hoi. hieu ve tham thuc va dao vi su tien*.