Perhaps you should try some spelling variations:
van pham » san pham, van phan, van phat
pham tai » pham thi, pham van
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
cau luc » cau truc, cau phuc
luc van » luoc van, luu van, duc van
va cau » van cau, va cac, va dau
cuc tu » cuc du, luc tu, cac tu
duc tu » luc tu

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: su sach ky ((nang xa) OR (lang xa)) hoi. hieu va cau luc van pham tai ((cuc tu) OR (duc tu))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) or (lang xa)) hoi. hieu va cau luc van pham tai ((cuc tu) OR (duc tu))~".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (lang xa)) hoi. hieu va cau luc van pham tai ((cuc tu) OR (duc tu))*.