Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nhan luc » nang luc
cau treo » cau theo, cau tren, cau triet
van nang » van quang, van ban, van dong
voi nang » voi hang, hoi nang, voi rang
hieu va » lieu va, hieu qua
va dinh » van dinh, va kinh, va tinh
dinh du » dinh duc, dinh cu, dinh tu
cu tren » tu tren, dua tren
va nhan » van nhan, ca nhan, va phan
luc va » duc va, tuc va, loc va
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: toc sach ((voi nang) or (van nang)) o hoi. hieu va nhan luc va dinh du ((cu tren) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((voi nang) OR (van nang)) o hoi. hieu va nhan luc va dinh du ((cu tren) OR (cau treo)).
• Adding a wildcard symbol may retrieve word variants: toc sach ((voi nang) or (van nang)) o hoi. hieu va nhan luc va dinh du ((cu tren) or (cau treo))*.