Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc 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 vi » hieu voi, hieu va, hieu ve
thuc va » thuc dan, thuc day
vai cua » dai cua, lai cua, bai cua
hai cua » thai cua, dai cua, hoi cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ty nang xa hoi. hieu vi pham ((thuc va) OR (thuc vat)) hanh ((vai cua) or (hai cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty nang xa hoi. hieu vi pham ((thuc va) OR (thuc vat)) hanh ((vai cua) OR (hai cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ty nang xa hoi. hieu vi pham ((thuc va) OR (thuc vat)) hanh ((vai cua) or (hai cua)) triet".
• Adding a wildcard symbol may retrieve word variants: doc sach ty nang xa hoi. hieu vi pham ((thuc va) OR (thuc vat)) hanh ((vai cua) or (hai cua)) triet*.