Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
va triet » va thiet, va trien, ve triet
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
va hanh » van hanh, va thanh, va danh
va cam » va cham, va cac, va cao
ve cac » va cac, vien cac
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ky nang xa hoi. hieu ((va cam) or (ve cac)) duc va hanh vi ((cua tu) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky nang xa hoi. hieu ((va cam) OR (ve cac)) duc va hanh vi ((cua tu) OR (va triet)).
• Adding a wildcard symbol may retrieve word variants: doc sach ky nang xa hoi. hieu ((va cam) or (ve cac)) duc va hanh vi ((cua tu) or (va triet))*.