Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cam duc » cam xuc, cao duc, pham duc
va hanh » van hanh, va thanh, va danh
cua tre » cuu tre, cua triet, dua tren
va cam » va cham, va cac, va cao
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc sach) or (thu hoach)) ky nang xa hoi. hieu va cam duc va hanh vi ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc sach) OR (thu hoach)) ky nang xa hoi. hieu va cam duc va hanh vi ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc sach) or (thu hoach)) ky nang xa hoi. hieu va cam duc va hanh vi ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: ((doc sach) or (thu hoach)) ky nang xa hoi. hieu va cam duc va hanh vi ((cua tre) OR (cua te))*.