Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va thanh » ban thanh, va tinh, le thanh
hieu va » lieu va, hieu qua
cam tuc » cam xuc, cam tu, nam thuc
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
va cam » va cham, va cac, va cao
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa

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 y nang ma hoi. hieu va cam tuc ((va thanh) or (gia thanh)) thai ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ma hoi. hieu va cam tuc ((va thanh) OR (gia thanh)) thai ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ma hoi. hieu va cam tuc ((va thanh) or (gia thanh)) thai ((cua tre) or (cuu tre))*.