Perhaps you should try some spelling variations:
su sach » so sach, vu sach
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
hieu va » lieu va, hieu qua
cao tuc » dao tuc, cao duc, cao suc
xa hanh » xa thanh, xa khanh, va hanh
vai cua » dai cua, lai cua, bai cua
hai cua » thai cua, dai cua, hoi cua
va cao » va cac, va co, va dao

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