Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
ca tren » cau tren, cu tren, la tren
va hanh » van hanh, va thanh, va danh
lao luc » bao luc
van lao » van dao, van bao, van lam
sach ky » sac ky, sach y, sach ty
te sach » toc sach
nang xa » nang x, lang xa, nang ma
lang ha » long ha
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va

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 ky ((nang xa) or (lang ha)) hoi. hieu van lao luc va hanh vi ((ca tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((nang xa) OR (lang ha)) hoi. hieu van lao luc va hanh vi ((ca tren) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: te sach ky ((nang xa) or (lang ha)) hoi. hieu van lao luc va hanh vi ((ca tren) or (cua tre))*.