Perhaps you should try some spelling variations:
dang xay » dang van, van xay
so sach » so sanh, bo sach, co sach
cam tuc » cam xuc, cam tu, nam thuc
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
va cam » va cham, va cac, va cao
xa dan » ca dan, xa dai, va dan
va cuu » va cau, va huu
va chu » va che, va cau, va chi

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty ((nang xa) or (dang xay)) hoi. hieu va cam tuc xa dan ((va cuu) OR (va chu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty ((nang xa) OR (dang xay)) hoi. hieu va cam tuc xa dan ((va cuu) OR (va chu)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty ((nang xa) or (dang xay)) hoi. hieu va cam tuc xa dan ((va cuu) OR (va chu)) tre".
• Adding a wildcard symbol may retrieve word variants: so sach ty ((nang xa) or (dang xay)) hoi. hieu va cam tuc xa dan ((va cuu) OR (va chu)) tre*.