Perhaps you should try some spelling variations:
nhan thuc » nhan luc, dan thuc, toan thuc
cham thuc » nham thuc, pham thuc, tham thuc
te sach » toc sach
ty nang » ty xang, ty hang, ly nang
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) OR (ky nang)) xa hoi. hieu ve ((cham thuc) or (nhan thuc)) va dau vi su hien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ty nang) OR (ky nang)) xa hoi. hieu ve ((cham thuc) OR (nhan thuc)) va dau vi su hien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ty nang) OR (ky nang)) xa hoi. hieu ve ((cham thuc) or (nhan thuc)) va dau vi su hien".
• Adding a wildcard symbol may retrieve word variants: te sach ((ty nang) OR (ky nang)) xa hoi. hieu ve ((cham thuc) or (nhan thuc)) va dau vi su hien*.