Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
dan cong » dang cong, van cong, dan dong
tu sach » su sach, te sach, tu cach
cac tuc » cac toc, cac tu, cac tac
cong cu » chung cu
mang xa » lang xa, mang may, dang xay
hieu va » lieu va, hieu qua
va dan » ca dan, va dao, va dau
tuc va » thuc va, truc va, tuc xa
cu tre » cu tren, cua tre, cuu tre

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 ((mang xa) or (nang x)) hoi. hieu va cac tuc va dan cong cu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty ((mang xa) OR (nang x)) hoi. hieu va cac tuc va dan cong cu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ty ((mang xa) or (nang x)) hoi. hieu va cac tuc va dan cong cu tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ty ((mang xa) or (nang x)) hoi. hieu va cac tuc va dan cong cu tre*.