Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
cau treo » cau theo, cau tren, cau triet
hieu va » lieu va, hieu qua
cam loc » cam lo
va dinh » van dinh, va kinh, vu dinh
va tinh » may tinh
y nang » ly nang, v nang, may nang
va cam » va cham, va cac, va cao
du cau » cu cau, da cau, di cau

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 ((y nang) or (ky nang)) xa hoi. hieu va cam loc ((va dinh) OR (va tinh)) du cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((y nang) OR (ky nang)) xa hoi. hieu va cam loc ((va dinh) OR (va tinh)) du cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((y nang) or (ky nang)) xa hoi. hieu va cam loc ((va dinh) OR (va tinh)) du cau treo".
• Adding a wildcard symbol may retrieve word variants: hoc sach ((y nang) or (ky nang)) xa hoi. hieu va cam loc ((va dinh) OR (va tinh)) du cau treo*.