Perhaps you should try some spelling variations:
tang hanh » tang thanh, dang hanh, nang hanh
duc tang » duc thang, duc tan, tuc tang
su sach » so sach, vu sach
ly nang » ly hang, ly vang, ly quang
hieu va » lieu va, hieu qua
va giao » van giao, va giai, va gia
vai cua » dai cua, lai cua, bai cua
hai cua » thai cua, dai cua, hoi cua
x hoi » xa hoi, o hoi, x ho

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