Perhaps you should try some spelling variations:
nhan thuc » nhan luc, dan thuc, toan thuc
cham thuc » nham thuc, pham thuc, tham thuc
dau tien » van tien
te sach » toc sach
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
hieu ve » hieu va, hieu van
su hien » su kien, su tien, thu hien
va dau » va dao
dau va » dau ve, lau va

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 ty xang xa hoi. hieu ve ((cham thuc) or (nhan thuc)) va dau va ((su hien) or (dau tien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty xang xa hoi. hieu ve ((cham thuc) OR (nhan thuc)) va dau va ((su hien) OR (dau tien)).
• Adding a wildcard symbol may retrieve word variants: te sach ty xang xa hoi. hieu ve ((cham thuc) or (nhan thuc)) va dau va ((su hien) or (dau tien))*.