Perhaps you should try some spelling variations:
ban hanh » ban hang
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
hieu ve » hieu van
hieu va » lieu va, hieu qua
duc ban » duc tan, duc van, dua ban
lai cua » hai cua, lai chau, thai cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty nang xa hoi. ((hieu ve) or (hieu va)) pham duc ban hanh ((lai cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty nang xa hoi. ((hieu ve) OR (hieu va)) pham duc ban hanh ((lai cua) OR (dai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: so sach ty nang xa hoi. ((hieu ve) or (hieu va)) pham duc ban hanh ((lai cua) or (dai cua)) tre*.