Perhaps you should try some spelling variations:
sach tham » sach nha
nhan luc » nang luc
nhan tai » hang tai, van tai, toan tai
sach thu » sach thue, cach thuc, sach nha
tai cua » thai cua, tai cuc, tri cua
hieu va » lieu va, hieu qua
va nhan » van nhan, ca nhan, va phan
luc va » duc va, tuc va, loc va
cua tu » cua tuc, cua su, cua cu
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai

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