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
va dat » va dao, va dau, va dap
vi su » va su, ki su, oi su
ve su » va su
kien » bien, vien, tien

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 ((vi su) OR (ve su)) kien~.
• 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 ((vi su) OR (ve su)) kien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang xa hoi. hieu ve ((cham thuc) or (nham thuc)) va dat ((vi su) OR (ve su)) kien".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang xa hoi. hieu ve ((cham thuc) or (nham thuc)) va dat ((vi su) OR (ve su)) kien*.