Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
cham luc » cham soc, cham cuu, chat lua
thanh ly » thanh lay, thanh ky, thanh le
hoc sach » hoc sinh, hoc cac, hoc anh
nhan luc » nang luc
hieu ve » hieu va, hieu van
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: ((toc sach) OR (hoc sach)) ky nang ma hoa. hieu ve ((cham luc) or (nhan luc)) gia thanh ly cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ky nang ma hoa. hieu ve ((cham luc) OR (nhan luc)) gia thanh ly cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (hoc sach)) ky nang ma hoa. hieu ve ((cham luc) or (nhan luc)) gia thanh ly cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (hoc sach)) ky nang ma hoa. hieu ve ((cham luc) or (nhan luc)) gia thanh ly cua tre*.