Perhaps you should try some spelling variations:
kham chua » kham pha
vanh tai » van tai, hanh tai, anh tai
so sach » bo sach, co sach, hoc sach
tai cua » thai cua, tai cuc, tri cua
va vanh » va van, va danh, va hanh
chua va » chuc va, chua may, chuan ha
va kham » va cham, va khao, va tham
hieu va » lieu va, hieu qua
nang co » nang doc, nang noi, nang hoc
so sanh » do sanh
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (so sanh)) thi ((nang co) OR (nang cao)) hoi. hieu va kham chua va vanh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) thi ((nang co) OR (nang cao)) hoi. hieu va kham chua va vanh tai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) or (so sanh)) thi ((nang co) OR (nang cao)) hoi. hieu va kham chua va vanh tai cua te".
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (so sanh)) thi ((nang co) OR (nang cao)) hoi. hieu va kham chua va vanh tai cua te*.