Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
va doanh » van doanh, vay doanh, va danh
bac truc » ba truc, bac trung, sach truc
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
tai cua » thai cua, tai cuc, tri cua
truc va » thuc va, thuc vat, trung va
van bac » van ban, van bao, van hac
nang xa » nang x, lang xa, nang ma
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) OR (doc sach)) ky ((nang xa) or (dang xay)) hoi. hieu van bac truc va doanh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky ((nang xa) OR (dang xay)) hoi. hieu van bac truc va doanh tai cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) ky ((nang xa) or (dang xay)) hoi. hieu van bac truc va doanh tai cua te*".