Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tham tuc » tham thuc, thai tuc, nham thuc
doc hoi » duoc hoi, hoc hoi, doi hoi
doc hai » hoc hai, duc hai, do hai
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
tuc va » thuc va, truc va, tuc xa
vi cuu » vi luu, vinh cuu

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 ((doc hoi) or (doc hai)). hieu va tham tuc va hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ((doc hoi) OR (doc hai)). hieu va tham tuc va hanh vi cuu tre.
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ((doc hoi) or (doc hai)). hieu va tham tuc va hanh vi cuu tre*.