Perhaps you should try some spelling variations:
thien van » thi van
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, lieu va, hieu ve
cau tren » cu tren, dau tren, ca tren
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
cam luc » cam xuc, cau luc
van tai » von tai, van tuan
cuu tre » cua tre, cau treo
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: toc sach ky nang xa hoi. ((hieu van) or (thien van)) cam luc va van tai ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. ((hieu van) OR (thien van)) cam luc va van tai ((cuu tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. ((hieu van) or (thien van)) cam luc va van tai ((cuu tre) or (cau tren))*.