Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
van hanh » van thanh, ban hanh, van anh
cac tren » ca tren, cau tren, tac tren
rac tren » ran tren, tac tren, sach tren
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
xuc van » duc van, luc van, vuc van
hanh va » hang va, hanh vi
va cam » va cham, va cac, va cao

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 (thuoc sach)) ky nang xa hoi. hieu va cam xuc van hanh va ((cac tren) OR (rac tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuoc sach)) ky nang xa hoi. hieu va cam xuc van hanh va ((cac tren) OR (rac tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuoc sach)) ky nang xa hoi. hieu va cam xuc van hanh va ((cac tren) OR (rac tren))".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuoc sach)) ky nang xa hoi. hieu va cam xuc van hanh va ((cac tren) OR (rac tren))*.