Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
va kinh » va tinh, qua kinh
van cam » van nam, van lam, van cau
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang
xuc va » duc va, tuc va, luc va
va cuu » va chu, va huu
va cau » van cau, va cac, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ((ty nang) or (ty hang)) xa hoi. hieu van cam xuc va kinh ((va cuu) OR (va cau)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((ty nang) OR (ty hang)) xa hoi. hieu van cam xuc va kinh ((va cuu) OR (va cau)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((ty nang) or (ty hang)) xa hoi. hieu van cam xuc va kinh ((va cuu) OR (va cau)) tre".
• Adding a wildcard symbol may retrieve word variants: hoc sach ((ty nang) or (ty hang)) xa hoi. hieu van cam xuc va kinh ((va cuu) OR (va cau)) tre*.