Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thuc van » thuc vat, thuc dan, thuc hanh
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
hanh di » hanh de, hang di, danh di
cua tre » cua te, cuu tre, cua triet
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: doc sach ky nang xa hoi. hieu va cam ((thuc van) OR (thuc va)) ((hanh di) or (hanh vi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky nang xa hoi. hieu va cam ((thuc van) OR (thuc va)) ((hanh di) OR (hanh vi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ky nang xa hoi. hieu va cam ((thuc van) OR (thuc va)) ((hanh di) or (hanh vi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: doc sach ky nang xa hoi. hieu va cam ((thuc van) OR (thuc va)) ((hanh di) or (hanh vi)) cua tre*.