Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
cac nuoc » cap nuoc, hoc nuoc, cua nuoc
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
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: su ((sach ky) OR (sach y)) nang xa hoi. hieu vien ((cac nuoc) or (dat nuoc)) van hanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach y)) nang xa hoi. hieu vien ((cac nuoc) OR (dat nuoc)) van hanh vi su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sach y)) nang xa hoi. hieu vien ((cac nuoc) or (dat nuoc)) van hanh vi su triet".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) OR (sach y)) nang xa hoi. hieu vien ((cac nuoc) or (dat nuoc)) van hanh vi su triet*.