Perhaps you should try some spelling variations:
thanh may » thanh tay, hanh may, thanh mau
va thanh » gia thanh, ban thanh, va tinh
tu sach » thu sach, su sach, tu cach
may duc » mai duc, my duc
cac toc » cac toi, cac nuoc, cac thoi
cac tuc » cac tu, cac tac, cac nuoc
duc tre » duoc tren, duc tien
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
te sach » toc sach
su hoa » su hoan, su hoat, su khoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (te sach)) ky dang su hoa. hieu ve ((cac tuc) OR (cac toc)) va thanh may duc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky dang su hoa. hieu ve ((cac tuc) OR (cac toc)) va thanh may duc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) ky dang su hoa. hieu ve ((cac tuc) OR (cac toc)) va thanh may duc tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ky dang su hoa. hieu ve ((cac tuc) OR (cac toc)) va thanh may duc tre*.