Perhaps you should try some spelling variations:
sach tham » sach nha
sach thu » sach thue, sach thieu, cach thuc
nhan luc » nang luc
han tai » hang tai, nhan tai, van tai
va nhan » van nhan, ca nhan, va phan
hieu va » lieu va, hieu qua
cua tuc » cua duc, cua thuoc, luat tuc
nang o » nang co, nang ho, nang ro
luc va » duc va, tuc va, loc va
va han » va phan, van han, va hanh
cua tu » cua su, cua cu, cua te
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach thu) or (sach tham)) nang o hoi. hieu va nhan luc va han tai ((cua tu) OR (cua tuc))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach thu) OR (sach tham)) nang o hoi. hieu va nhan luc va han tai ((cua tu) OR (cua tuc)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach thu) or (sach tham)) nang o hoi. hieu va nhan luc va han tai ((cua tu) OR (cua tuc))".
• Adding a wildcard symbol may retrieve word variants: te ((sach thu) or (sach tham)) nang o hoi. hieu va nhan luc va han tai ((cua tu) OR (cua tuc))*.