Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cau tren » cu tren, dau tren, ca tren
van hanh » van thanh, ban hanh, van anh
cau treo » cau theo, cau triet, cau trieu
vien cac » vien bach, vien dai, vien da
sach ky » sac ky, sach y, sach ty
xuc van » duc van, luc van, vuc van
nang xa » nang x, lang xa, nang ma
ve cham » va cham, ve chat, vu cham

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 ((vien cac) or (ve cham)) xuc van hanh vi ((cau tren) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. hieu ((vien cac) OR (ve cham)) xuc van hanh vi ((cau tren) OR (cau treo)).
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. hieu ((vien cac) or (ve cham)) xuc van hanh vi ((cau tren) or (cau treo))*.