Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
dang xay » dang van, van xay
tu sach » thu sach, su sach, te sach
xa hanh » xa thanh, xa khanh, va hanh
dau tuc » dau tu, dao tuc, cau truc
van dau » van dao, phan dau
cuu tre » cua tre, cau tren, cau treo
sach ky » sac ky, sach y, sach ty
mang xa » lang xa, mang may, mang cua
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: tu sach ky ((((mang xa) OR (dang xay))) or (nang x)) hoi. hieu van dau tuc xa hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((((mang xa) OR (dang xay))) OR (nang x)) hoi. hieu van dau tuc xa hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((((mang xa) OR (dang xay))) or (nang x)) hoi. hieu van dau tuc xa hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((((mang xa) OR (dang xay))) or (nang x)) hoi. hieu van dau tuc xa hanh vi cuu tre*.