Perhaps you should try some spelling variations:
hieu vien » hieu hien, thieu nien, hieu tieng
hieu viec » nhieu viec, hieu ve, sieu viet
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
va tinh » may tinh
tinh vi » trinh vi, tinh voi, tinh 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: tu sach ty nang x ho. ((hieu vien) OR (hieu viec)) cac nuoc va tinh vi su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang x ho. ((hieu vien) OR (hieu viec)) cac nuoc va tinh vi su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang x ho. ((hieu vien) OR (hieu viec)) cac nuoc va tinh vi su triet*.