Perhaps you should try some spelling variations:
dang xay » dang van, van xay
qua nam » quan nam, cua nam, quang nam
qua ban » cua ban, qua quan
qua van » quan van, qua san, qua va
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky ((dang xay) or (nang ma)) hoi. hieu qua nam ((qua van) or (qua ban)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((dang xay) OR (nang ma)) hoi. hieu qua nam ((qua van) OR (qua ban)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((dang xay) or (nang ma)) hoi. hieu qua nam ((qua van) or (qua ban)) hanh vi cua tre*.