Perhaps you should try some spelling variations:
bach tuoc » sach duoc, sach nuoc
su triet » su viet, su tien, ve triet
hanh tai » thanh tai, hang tai, han tai
va hanh » van hanh, va thanh, va danh
su sach » vu sach
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
so sach » so sanh, bo sach, co sach
bac tuc » bac tu, bac thua
y nang » ky nang, ly nang, v nang
tai su » tai so, tai tu, lai 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) OR (so sach)) y nang xa hoi. hieu va ((bac tuc) or (bach tuoc)) va hanh tai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) y nang xa hoi. hieu va ((bac tuc) OR (bach tuoc)) va hanh tai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (so sach)) y nang xa hoi. hieu va ((bac tuc) or (bach tuoc)) va hanh tai su triet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) OR (so sach)) y nang xa hoi. hieu va ((bac tuc) or (bach tuoc)) va hanh tai su triet*.