Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hanh va » hanh vi
lao luc » bao luc
sach ky » sach y, sach ty, sach kem
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
sac ky » cac ky, sai ky
luc va » duc va, tuc va, loc va
va lao » van lao, va dao, va bao

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sac ky)) lang xa hoi. hieu va lao luc va ((hanh va) or (hang va)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) lang xa hoi. hieu va lao luc va ((hanh va) OR (hang va)) cau tren.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) lang xa hoi. hieu va lao luc va ((hanh va) or (hang va)) cau tren*.