Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu vien » hieu hien, hieu viec, thieu nien
van triet » va triet, van thiet, van trieu
vien cac » vien bach, vien dai, vien da
ty nang » ty xang, ty hang, ly nang
cac dac » cac dan, cac dai, cac bac
hanh ve » hanh va, hanh kem
dac va » duc va, day va, dat va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ((ty nang) OR (ky nang)) xa hoi. hieu vien cac dac va ((hanh ve) or (hanh vi)) van triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ((ty nang) OR (ky nang)) xa hoi. hieu vien cac dac va ((hanh ve) OR (hanh vi)) van triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ((ty nang) OR (ky nang)) xa hoi. hieu vien cac dac va ((hanh ve) or (hanh vi)) van triet".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ((ty nang) OR (ky nang)) xa hoi. hieu vien cac dac va ((hanh ve) or (hanh vi)) van triet*.