Perhaps you should try some spelling variations:
sinh thai » dinh thi
hanh thai » nhanh thai, hinh thai, hanh tai
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
cuu tre » cua tre, cau tren, cau treo
duc van » duc va, duc tan, duc manh
sach ty » sach y, sach tu, sach thu
cac duc » cac du, cao duc, cac dac
van cac » van hac, van cau, van bac
ty nang » ky nang, ty xang, ty hang
nang o » nang co, nang ho, nang ro
cua te » cua tu
o hai » co hai, so hai, o lai

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang o hai. hieu van cac duc van ((hanh thai) OR (sinh thai)) ((cuu tre) OR (cua te))~.
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang o hai. hieu van cac duc van ((hanh thai) or (sinh thai)) ((cuu tre) or (cua te))*.