Perhaps you should try some spelling variations:
pham tai » pham thi, pham van
thu sach » thuat sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
tu sach » su sach, te sach, tu cach
van cau » van dau, van hau, van chat
nang xa » nang x, nang ma, mang xa
duc san » duc tan, duc van, dac san
cau duc » cao duc, cau luc, chu duc
lang xa » lang ha, dang xay, lang van
cuc tu » cuc du, luc tu, duc tu

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) OR (thu sach)) ty ((nang xa) or (lang xa)) hoi. hieu van cau duc san pham tai cuc tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty ((nang xa) OR (lang xa)) hoi. hieu van cau duc san pham tai cuc tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ty ((nang xa) or (lang xa)) hoi. hieu van cau duc san pham tai cuc tu".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ty ((nang xa) or (lang xa)) hoi. hieu van cau duc san pham tai cuc tu*.