Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
dau tuc » dau tu, dao tuc, cau truc
tuc van » thuc van, truc van, tuc va
doi cua » hoi cua
va dau » va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach thu ((nang xa) or (lang xa)) hoi. lieu va dau tuc van hanh ((doi cua) OR (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thu ((nang xa) OR (lang xa)) hoi. lieu va dau tuc van hanh ((doi cua) OR (dai cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thu ((nang xa) or (lang xa)) hoi. lieu va dau tuc van hanh ((doi cua) OR (dai cua)) tre*".