Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
toc sach » hoc sach, doc sach, thuoc sach
nham thu » nham thuc, nam thu, pham thu
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
su hien » su kien, su tien, thu hien
va dat » va dao, va dau, va dap
dat vi » dat va, hat vi, dat ve
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: toc sach ky lang xa hoi. hieu ve ((pham thuc) or (nham thu)) va dat vi su hien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang xa hoi. hieu ve ((pham thuc) OR (nham thu)) va dat vi su hien.
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. hieu ve ((pham thuc) or (nham thu)) va dat vi su hien*.