Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
va cham » va chat, va tham
hanh ly » khanh ly, hanh ky, hang ly
ve cham » ve chat, vu cham, ve chim
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
ly cua » le cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ky nang ma hoa. hieu ((ve cham) or (va cham)) cuu van hanh ly cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang ma hoa. hieu ((ve cham) OR (va cham)) cuu van hanh ly cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ky nang ma hoa. hieu ((ve cham) or (va cham)) cuu van hanh ly cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ky nang ma hoa. hieu ((ve cham) or (va cham)) cuu van hanh ly cua tre*.