Perhaps you should try some spelling variations:
qua giao » cua giao, qua gia, qua giai
tan hanh » tan thanh, tang hanh, toan hanh
tu sach » thu sach, su sach, te sach
sach ly » sach y, sach lo, sach ty
ly nang » ky nang, ly hang, ly vang
vai cua » dai cua, lai cua, bai cua
hai cua » thai cua, dai cua, hoi cua
x hoi » xa hoi, o hoi, 5 hoi

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 ly nang ((x hoi) OR (x ho)). hieu qua giao duc tan hanh ((vai cua) or (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ly nang ((x hoi) OR (x ho)). hieu qua giao duc tan hanh ((vai cua) OR (hai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ly nang ((x hoi) OR (x ho)). hieu qua giao duc tan hanh ((vai cua) or (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ly nang ((x hoi) OR (x ho)). hieu qua giao duc tan hanh ((vai cua) or (hai cua)) tre*.