Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, te sach, tu cach
va hanh » van hanh, va thanh, va danh
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
su sach » so sach, vu sach
am hoc » ad hoc
va cuu » va cau, va huu
va chu » va che, va cau, va chi
van am » van nam, van lam, van dam

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) or (su sach)) ty nang xa hoi. hieu van am hoc va hanh ((va cuu) or (va chu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ty nang xa hoi. hieu van am hoc va hanh ((va cuu) OR (va chu)) tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ty nang xa hoi. hieu van am hoc va hanh ((va cuu) or (va chu)) tre*.