Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
thanh te » thanh ve, thanh de, thanh le
nang ma » tang ma, sang ma, nang cao
van cam » van nam, van lam, van cau
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
tuc va » thuc va, truc va, duc va
te cua » tue cua, le cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y nang ma hoi. hieu van cam ((tuc va) or (tuc xa)) thanh te cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang ma hoi. hieu van cam ((tuc va) OR (tuc xa)) thanh te cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach y nang ma hoi. hieu van cam ((tuc va) or (tuc xa)) thanh te cua tre*.