Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
va danh » va dinh, va dan, va hanh
hai cua » thai cua, hoi cua, lai cua
ve cac » va cac, vien cac
cac do » cac don, cac doi, cac du
do va » do van, so va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang xa hoi. hieu ve cac do va danh ((hai cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang xa hoi. hieu ve cac do va danh ((hai cua) OR (dai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang xa hoi. hieu ve cac do va danh ((hai cua) or (dai cua)) tre*.