Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
ty nang » ky nang, ty hang, ty nong
ly nang » ky nang, ly hang, ly vang
va tinh » may tinh
tinh ki » trinh ki, tinh vi, tinh kien
ki su » ky 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) OR (ly nang))) or (ty xang)) x ho. hieu vien cac nuoc va tinh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((((ty nang) OR (ly nang))) OR (ty xang)) x ho. hieu vien cac nuoc va tinh ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((((ty nang) OR (ly nang))) or (ty xang)) x ho. hieu vien cac nuoc va tinh ki su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((((ty nang) OR (ly nang))) or (ty xang)) x ho. hieu vien cac nuoc va tinh ki su triet*.