Perhaps you should try some spelling variations:
cham thuc » pham thuc, tham thuc, pham thuoc
nham thuc » nhan thuc, nam thuc, nham thu
te sach » toc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
su hien » su kien, su tien, thu hien
va dau » va dao
dau vi » dau ve, dau va, dat vi
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 ty nang xa hoi. hieu ve ((cham thuc) or (nham thuc)) va dau vi su hien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang xa hoi. hieu ve ((cham thuc) OR (nham thuc)) va dau vi su hien.
• Adding a wildcard symbol may retrieve word variants: te sach ty nang xa hoi. hieu ve ((cham thuc) or (nham thuc)) va dau vi su hien*.