Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
hieu van » hieu va, thien van, lieu va
hau duc » huu duc, ha duc, pham duc
hanh ve » hanh vi, hanh va
duc van » duc va, duc tan, duc manh
van hau » van ha, van hai, van dau
nang ma » tang ma, sang ma, nang cao
cuu tre » cua tre, cau tren, cau treo
v nang » va nang, vu nang, van nang

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 (doc sach)) v nang ma hoa. hieu van hau duc van ((hanh ve) or (hanh kem)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) v nang ma hoa. hieu van hau duc van ((hanh ve) OR (hanh kem)) cuu tre.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) v nang ma hoa. hieu van hau duc van ((hanh ve) or (hanh kem)) cuu tre*.