Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
cap nuoc » dat nuoc
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
y nang » ky nang, ly nang, v nang
ve cap » ve cac, le cap, ve cai

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 (thuoc sach)) y nang ma hoa. hieu ve cap nuoc ((van hanh) or (ban hanh)) tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) y nang ma hoa. hieu ve cap nuoc ((van hanh) OR (ban hanh)) tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (thuoc sach)) y nang ma hoa. hieu ve cap nuoc ((van hanh) or (ban hanh)) tai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (thuoc sach)) y nang ma hoa. hieu ve cap nuoc ((van hanh) or (ban hanh)) tai cua tre*.