Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
cham thuc » pham thuc, tham thuc, pham thuoc
te sach » toc sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
su hien » su kien, su tien, thu hien
va dat » va dao, va dau, va dap
dat vi » dat va, hat vi, dat ve
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 ((cham thuc) or (nham thuc)) va dat vi su hien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((nang xa) OR (lang xa)) hoi. hieu ve ((cham thuc) OR (nham thuc)) va dat vi su hien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky ((nang xa) OR (lang xa)) hoi. hieu ve ((cham thuc) or (nham thuc)) va dat vi su hien".
• Adding a wildcard symbol may retrieve word variants: te sach ky ((nang xa) OR (lang xa)) hoi. hieu ve ((cham thuc) or (nham thuc)) va dat vi su hien*.