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
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
su hien » su kien, su tien, thu hien
va dat » va dao, va dau, va dap
dat ki » dat vi, dat xi
ki su » ky 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 hoi. hieu ve ((cham thuc) or (nham thuc)) va dat ki su hien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang xa hoi. hieu ve ((cham thuc) OR (nham thuc)) va dat ki su hien.
• Adding a wildcard symbol may retrieve word variants: te sach ky nang xa hoi. hieu ve ((cham thuc) or (nham thuc)) va dat ki su hien*.