Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
sach tu » sach thu, cach tu, sach uu
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
sach ty » sach y, sach thu, xach tay
cac tu » cac thu, cach tu, tac tu
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
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: thu ((sach ty) OR (sach tu)) nang xa hoi. hieu ve ((cac tu) or (cac du)) va dan vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ty) OR (sach tu)) nang xa hoi. hieu ve ((cac tu) OR (cac du)) va dan vi su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ty) OR (sach tu)) nang xa hoi. hieu ve ((cac tu) or (cac du)) va dan vi su triet".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ty) OR (sach tu)) nang xa hoi. hieu ve ((cac tu) or (cac du)) va dan vi su triet*.