Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
cao luc » bao luc, cao duc, cao suc
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
nang ro » nang co, nang ho, nang ra
sach v » sach va, sach y, sach 2
nang o » nang co, nang ho, nang x
di cua » dai cua, doi cua, de cua
va cao » va cac, va co, va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach v ((nang o) OR (nang ro)) hoi. hieu va cao luc ((va danh) or (va hanh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v ((nang o) OR (nang ro)) hoi. hieu va cao luc ((va danh) OR (va hanh)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach v ((nang o) OR (nang ro)) hoi. hieu va cao luc ((va danh) or (va hanh)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach v ((nang o) OR (nang ro)) hoi. hieu va cao luc ((va danh) or (va hanh)) di cua tre*.